Import C bindings from NixOS/nix#8699

Co-authored-by: Yorick van Pelt <yorick@yorickvanpelt.nl> Co-authored-by: José Luis Lafuente <jose.lafuente@tweag.io> Change-Id: I48aa262d880aa75aa5b230553f663c35c283d5f6
libexpr: Lessen const bound on Value::listElems() const
2024-03-17 16:38:04 +00:00 · 2024-03-17 16:25:12 +00:00 · 2024-03-17 16:06:00 +00:00 · 2024-03-17 16:04:36 +00:00 · 2024-03-16 19:23:19 -06:00 · 2024-03-15 18:55:59 -06:00
33 changed files with 3793 additions and 332 deletions
--- a/flake.nix
+++ b/flake.nix
@ -48,50 +48,6 @@
            })
            stdenvs);

-      baseFiles =
-        # .gitignore has already been processed, so any changes in it are irrelevant
-        # at this point. It is not represented verbatim for test purposes because
-        # that would interfere with repo semantics.
-        fileset.fileFilter (f: f.name != ".gitignore") ./.;
-
-      configureFiles = fileset.unions [
-        ./.version
-        ./configure.ac
-        ./m4
-        # TODO: do we really need README.md? It doesn't seem used in the build.
-        ./README.md
-      ];
-
-      topLevelBuildFiles = fileset.unions [
-        ./local.mk
-        ./Makefile
-        ./Makefile.config.in
-        ./mk
-      ];
-
-      functionalTestFiles = fileset.unions [
-        ./tests/functional
-        ./tests/unit
-        (fileset.fileFilter (f: lib.strings.hasPrefix "nix-profile" f.name) ./scripts)
-      ];
-
-      nixSrc = fileset.toSource {
-        root = ./.;
-        fileset = fileset.intersection baseFiles (fileset.unions [
-          configureFiles
-          topLevelBuildFiles
-          ./boehmgc-coroutine-sp-fallback.diff
-          ./doc
-          ./misc
-          ./precompiled-headers.h
-          ./src
-          ./unit-test-data
-          ./COPYING
-          ./scripts/local.mk
-          functionalTestFiles
-        ]);
-      };
-
      # Memoize nixpkgs for different platforms for efficiency.
      nixpkgsFor = forAllSystems
        (system: let
@ -118,120 +74,6 @@
          cross = forAllCrossSystems (crossSystem: make-pkgs crossSystem "stdenv");
        });

-      commonDeps =
-        { pkgs
-        , isStatic ? pkgs.stdenv.hostPlatform.isStatic
-        }:
-        with pkgs; rec {
-        # Use "busybox-sandbox-shell" if present,
-        # if not (legacy) fallback and hope it's sufficient.
-        sh = pkgs.busybox-sandbox-shell or (busybox.override {
-          useMusl = true;
-          enableStatic = true;
-          enableMinimal = true;
-          extraConfig = ''
-            CONFIG_FEATURE_FANCY_ECHO y
-            CONFIG_FEATURE_SH_MATH y
-            CONFIG_FEATURE_SH_MATH_64 y
-
-            CONFIG_ASH y
-            CONFIG_ASH_OPTIMIZE_FOR_SIZE y
-
-            CONFIG_ASH_ALIAS y
-            CONFIG_ASH_BASH_COMPAT y
-            CONFIG_ASH_CMDCMD y
-            CONFIG_ASH_ECHO y
-            CONFIG_ASH_GETOPTS y
-            CONFIG_ASH_INTERNAL_GLOB y
-            CONFIG_ASH_JOB_CONTROL y
-            CONFIG_ASH_PRINTF y
-            CONFIG_ASH_TEST y
-          '';
-        });
-
-        configureFlags =
-          lib.optionals stdenv.isLinux [
-            "--with-boost=${boost}/lib"
-            "--with-sandbox-shell=${sh}/bin/busybox"
-          ]
-          ++ lib.optionals (stdenv.isLinux && !(isStatic && stdenv.system == "aarch64-linux")) [
-            "LDFLAGS=-fuse-ld=gold"
-          ];
-
-        testConfigureFlags = [
-          "RAPIDCHECK_HEADERS=${lib.getDev rapidcheck}/extras/gtest/include"
-        ];
-
-        internalApiDocsConfigureFlags = [
-          "--enable-internal-api-docs"
-        ];
-
-        changelog-d = pkgs.buildPackages.callPackage ./misc/changelog-d.nix { };
-
-        nativeBuildDeps =
-          [
-            buildPackages.bison
-            buildPackages.flex
-            (lib.getBin buildPackages.lowdown)
-            buildPackages.mdbook
-            buildPackages.mdbook-linkcheck
-            buildPackages.autoconf-archive
-            buildPackages.autoreconfHook
-            buildPackages.pkg-config
-
-            # Tests
-            buildPackages.git
-            buildPackages.mercurial # FIXME: remove? only needed for tests
-            buildPackages.jq # Also for custom mdBook preprocessor.
-          ]
-          ++ lib.optionals stdenv.hostPlatform.isLinux [(buildPackages.util-linuxMinimal or buildPackages.utillinuxMinimal)]
-          # Official releases don't have rl-next, so we don't need to compile a changelog
-          ++ lib.optional (!officialRelease && buildUnreleasedNotes) changelog-d
-          ;
-
-        buildDeps =
-          [ curl
-            bzip2 xz brotli editline
-            openssl sqlite
-            libarchive
-            boost
-            lowdown
-            libsodium
-          ]
-          ++ lib.optionals stdenv.isLinux [libseccomp]
-          ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid;
-
-        checkDeps = [
-          gtest
-          rapidcheck
-        ];
-
-        internalApiDocsDeps = [
-          buildPackages.doxygen
-        ];
-
-        awsDeps = lib.optional (stdenv.isLinux || stdenv.isDarwin)
-          (aws-sdk-cpp.override {
-            apis = ["s3" "transfer"];
-            customMemoryManagement = false;
-          });
-
-        propagatedDeps =
-          [ ((boehmgc.override {
-              enableLargeConfig = true;
-            }).overrideAttrs(o: {
-              patches = (o.patches or []) ++ [
-                ./boehmgc-coroutine-sp-fallback.diff
-
-                # https://github.com/ivmai/bdwgc/pull/586
-                ./boehmgc-traceable_allocator-public.diff
-              ];
-            })
-            )
-            nlohmann_json
-          ];
-      };
-
      installScriptFor = systems:
        with nixpkgsFor.x86_64-linux.native;
        runCommand "installer-script"
@ -266,51 +108,40 @@
            echo "file installer $out/install" >> $out/nix-support/hydra-build-products
          '';

-      testNixVersions = pkgs: client: daemon: with commonDeps { inherit pkgs; }; with pkgs.lib; pkgs.stdenv.mkDerivation {
+      testNixVersions = pkgs: client: daemon: let
+        nix = pkgs.callPackage ./package.nix {
+          pname =
+            "nix-tests"
+            + lib.optionalString
+            (lib.versionAtLeast daemon.version "2.4pre20211005" &&
+            lib.versionAtLeast client.version "2.4pre20211005")
+            "-${client.version}-against-${daemon.version}";
+
+            inherit fileset;
+        };
+      in nix.overrideAttrs (prevAttrs: {
        NIX_DAEMON_PACKAGE = daemon;
        NIX_CLIENT_PACKAGE = client;
-        name =
-          "nix-tests"
-          + optionalString
-            (versionAtLeast daemon.version "2.4pre20211005" &&
-             versionAtLeast client.version "2.4pre20211005")
-            "-${client.version}-against-${daemon.version}";
-        inherit version;

-        src = fileset.toSource {
-          root = ./.;
-          fileset = fileset.intersection baseFiles (fileset.unions [
-            configureFiles
-            topLevelBuildFiles
-            functionalTestFiles
-          ]);
-        };
-
-        VERSION_SUFFIX = versionSuffix;
-
-        nativeBuildInputs = nativeBuildDeps;
-        buildInputs = buildDeps ++ awsDeps ++ checkDeps;
-        propagatedBuildInputs = propagatedDeps;
-
-        enableParallelBuilding = true;
-
-        configureFlags =
-          testConfigureFlags # otherwise configure fails
-          ++ [ "--disable-build" ];
        dontBuild = true;
        doInstallCheck = true;

+        configureFlags = [
+          "RAPIDCHECK_HEADERS=${lib.getDev pkgs.rapidcheck}/extras/gtest/include"
+          "--disable-build"
+        ];
+
        installPhase = ''
          mkdir -p $out
        '';

-        installCheckPhase = (optionalString pkgs.stdenv.hostPlatform.isDarwin ''
+        installCheckPhase = (lib.optionalString pkgs.stdenv.hostPlatform.isDarwin ''
          export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
        '') + ''
          mkdir -p src/nix-channel
          make installcheck -j$NIX_BUILD_CORES -l$NIX_BUILD_CORES
        '';
-      };
+      });

      binaryTarball = nix: pkgs:
        let
@ -387,109 +218,54 @@
          '';

      overlayFor = getStdenv: final: prev:
-        let currentStdenv = getStdenv final; in
        {
          nixStable = prev.nix;

-          nix =
-          with final;
-          with commonDeps {
-            inherit pkgs;
-            inherit (currentStdenv.hostPlatform) isStatic;
-          };
-          let
-            canRunInstalled = currentStdenv.buildPlatform.canExecute currentStdenv.hostPlatform;
-          in currentStdenv.mkDerivation (finalAttrs: {
-            name = "nix-${version}";
-            inherit version;
+          # Forward from the previous stage as we don’t want it to pick the lowdown override
+          nixUnstable = prev.nixUnstable;

-            src = nixSrc;
-            VERSION_SUFFIX = versionSuffix;
+          changelog-d = final.buildPackages.callPackage ./misc/changelog-d.nix { };
+          boehmgc-nix = (final.boehmgc.override {
+            enableLargeConfig = true;
+          }).overrideAttrs (o: {
+            patches = (o.patches or [ ]) ++ [
+              ./boehmgc-coroutine-sp-fallback.diff

-            outputs = [ "out" "dev" "doc" ];
-
-            nativeBuildInputs = nativeBuildDeps;
-            buildInputs = buildDeps
-              # There have been issues building these dependencies
-              ++ lib.optionals (currentStdenv.hostPlatform == currentStdenv.buildPlatform) awsDeps
-              ++ lib.optionals finalAttrs.doCheck checkDeps;
-
-            propagatedBuildInputs = propagatedDeps;
-
-            disallowedReferences = [ boost ];
-
-            preConfigure = lib.optionalString (! currentStdenv.hostPlatform.isStatic)
-              ''
-                # Copy libboost_context so we don't get all of Boost in our closure.
-                # https://github.com/NixOS/nixpkgs/issues/45462
-                mkdir -p $out/lib
-                cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
-                rm -f $out/lib/*.a
-                ${lib.optionalString currentStdenv.hostPlatform.isLinux ''
-                  chmod u+w $out/lib/*.so.*
-                  patchelf --set-rpath $out/lib:${currentStdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
-                ''}
-                ${lib.optionalString currentStdenv.hostPlatform.isDarwin ''
-                  for LIB in $out/lib/*.dylib; do
-                    chmod u+w $LIB
-                    install_name_tool -id $LIB $LIB
-                    install_name_tool -delete_rpath ${boost}/lib/ $LIB || true
-                  done
-                  install_name_tool -change ${boost}/lib/libboost_system.dylib $out/lib/libboost_system.dylib $out/lib/libboost_thread.dylib
-                ''}
-              '';
-
-            configureFlags = configureFlags ++
-              [ "--sysconfdir=/etc" ] ++
-              lib.optional stdenv.hostPlatform.isStatic "--enable-embedded-sandbox-shell" ++
-              [ (lib.enableFeature finalAttrs.doCheck "tests") ] ++
-              lib.optionals finalAttrs.doCheck testConfigureFlags ++
-              lib.optional (!canRunInstalled) "--disable-doc-gen";
-
-            enableParallelBuilding = true;
-
-            makeFlags = "profiledir=$(out)/etc/profile.d PRECOMPILE_HEADERS=1";
-
-            doCheck = true;
-
-            installFlags = "sysconfdir=$(out)/etc";
-
-            postInstall = ''
-              mkdir -p $doc/nix-support
-              echo "doc manual $doc/share/doc/nix/manual" >> $doc/nix-support/hydra-build-products
-              ${lib.optionalString currentStdenv.hostPlatform.isStatic ''
-              mkdir -p $out/nix-support
-              echo "file binary-dist $out/bin/nix" >> $out/nix-support/hydra-build-products
-              ''}
-              ${lib.optionalString currentStdenv.isDarwin ''
-              install_name_tool \
-                -change ${boost}/lib/libboost_context.dylib \
-                $out/lib/libboost_context.dylib \
-                $out/lib/libnixutil.dylib
-              ''}
-            '';
-
-            doInstallCheck = finalAttrs.doCheck;
-            installCheckFlags = "sysconfdir=$(out)/etc";
-            installCheckTarget = "installcheck"; # work around buggy detection in stdenv
-
-            preInstallCheck = lib.optionalString stdenv.hostPlatform.isDarwin ''
-              export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
-            '';
-
-            separateDebugInfo = !currentStdenv.hostPlatform.isStatic;
-
-            strictDeps = true;
-
-            hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
-
-            passthru.perl-bindings = final.callPackage ./perl {
-              inherit fileset;
-              stdenv = currentStdenv;
-            };
-
-            meta.platforms = lib.platforms.unix;
+              # https://github.com/ivmai/bdwgc/pull/586
+              ./boehmgc-traceable_allocator-public.diff
+            ];
          });
+
+          default-busybox-sandbox-shell = final.busybox.override {
+            useMusl = true;
+            enableStatic = true;
+            enableMinimal = true;
+            extraConfig = ''
+              CONFIG_FEATURE_FANCY_ECHO y
+              CONFIG_FEATURE_SH_MATH y
+              CONFIG_FEATURE_SH_MATH_64 y
+
+              CONFIG_ASH y
+              CONFIG_ASH_OPTIMIZE_FOR_SIZE y
+
+              CONFIG_ASH_ALIAS y
+              CONFIG_ASH_BASH_COMPAT y
+              CONFIG_ASH_CMDCMD y
+              CONFIG_ASH_ECHO y
+              CONFIG_ASH_GETOPTS y
+              CONFIG_ASH_INTERNAL_GLOB y
+              CONFIG_ASH_JOB_CONTROL y
+              CONFIG_ASH_PRINTF y
+              CONFIG_ASH_TEST y
+            '';
+          };
+
+          nix = final.callPackage ./package.nix {
+            inherit (final) stdenv;
+            inherit versionSuffix fileset;
+            boehmgc = final.boehmgc-nix;
+            busybox-sandbox-shell = final.busybox-sandbox-shell or final.default-busybox-sandbox-shell;
+          };
        };

    in {
@ -514,31 +290,52 @@
        dockerImage = lib.genAttrs linux64BitSystems (system: self.packages.${system}.dockerImage);

        # API docs for Nix's unstable internal C++ interfaces.
-        internal-api-docs =
-          with nixpkgsFor.x86_64-linux.native;
-          with commonDeps { inherit pkgs; };
+        internal-api-docs = let
+          nixpkgs = nixpkgsFor.x86_64-linux.native;
+          inherit (nixpkgs) pkgs;

-          stdenv.mkDerivation {
+          nix = pkgs.callPackage ./package.nix {
+            inherit versionSuffix fileset officialRelease buildUnreleasedNotes;
+            inherit (pkgs) changelog-d;
+            boehmgc = pkgs.boehmgc-nix;
+            busybox-sandbox-shell = pkgs.busybox-sandbox-shell;
+          };
+        in
+          nix.overrideAttrs (prev: {
            pname = "nix-internal-api-docs";
-            inherit version;

-            src = nixSrc;
+            outputs = [ "out" ];
+            separateDebugInfo = false;

-            configureFlags = testConfigureFlags ++ internalApiDocsConfigureFlags;
+            nativeBuildInputs = prev.nativeBuildInputs ++ [ pkgs.doxygen ];

-            nativeBuildInputs = nativeBuildDeps;
-            buildInputs = buildDeps ++ propagatedDeps
-              ++ awsDeps ++ checkDeps ++ internalApiDocsDeps;
+            # Depropagate the build inputs for the docs build.
+            propagatedBuildInputs = [ ];
+            buildInputs = prev.buildInputs ++ [ pkgs.buildPackages.doxygen ] ++ [
+              pkgs.gtest
+              pkgs.rapidcheck
+            ] ++ prev.propagatedBuildInputs;

-            dontBuild = true;
+            configureFlags = prev.configureFlags ++ [
+              "--enable-internal-api-docs"
+              "RAPIDCHECK_HEADERS=${lib.getDev pkgs.rapidcheck}/extras/gtest/include"
+            ];

            installTargets = [ "internal-api-html" ];

+            # Convince the package.nix logic that we're building,
+            # but don't actually run the build phase.
+            env.dontBuild = true;
+
+            doCheck = false;
+            doInstallCheck = false;
+
            postInstall = ''
              mkdir -p $out/nix-support
-              echo "doc internal-api-docs $out/share/doc/nix/internal-api/html" >> $out/nix-support/hydra-build-products
+              echo "doc internal-api-docs $out/share/doc/nix/internal-api/html" > $out/nix-support/hydra-build-products
+              rm $out/lib -rf
            '';
-          };
+          });

        # System tests.
        tests = import ./tests/nixos { inherit lib nixpkgs nixpkgsFor; } // {
@ -588,7 +385,7 @@
        rl-next =
          let pkgs = nixpkgsFor.${system}.native;
          in pkgs.buildPackages.runCommand "test-rl-next-release-notes" { } ''
-          LANG=C.UTF-8 ${(commonDeps { inherit pkgs; }).changelog-d}/bin/changelog-d ${./doc/manual/rl-next} >$out
+          LANG=C.UTF-8 ${pkgs.changelog-d}/bin/changelog-d ${./doc/manual/rl-next} >$out
        '';
      } // (lib.optionalAttrs (builtins.elem system linux64BitSystems)) {
        dockerImage = self.hydraJobs.dockerImage.${system};
@ -629,36 +426,26 @@
      devShells = let
        makeShell = pkgs: stdenv:
          let
-            canRunInstalled = stdenv.buildPlatform.canExecute stdenv.hostPlatform;
+            nix = pkgs.callPackage ./package.nix {
+              inherit stdenv versionSuffix fileset;
+              boehmgc = pkgs.boehmgc-nix;
+              busybox-sandbox-shell = pkgs.busybox-sandbox-shell or pkgs.default-busybox-sandbox;
+            };
          in
-          with commonDeps { inherit pkgs; };
-          stdenv.mkDerivation {
-            name = "nix";
+            nix.overrideAttrs (prev: {
+              nativeBuildInputs = prev.nativeBuildInputs
+                ++ lib.optional (stdenv.cc.isClang && !stdenv.buildPlatform.isDarwin) pkgs.buildPackages.bear
+                ++ lib.optional
+                  (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform)
+                  pkgs.buildPackages.clang-tools;
+                src = null;

-            outputs = [ "out" "dev" "doc" ];
+              doInstallCheck = false;
+              doCheck = false;
+              installFlags = "sysconfdir=$(out)/etc";
+              strictDeps = false;

-            nativeBuildInputs = nativeBuildDeps
-              ++ lib.optional (stdenv.cc.isClang && !stdenv.buildPlatform.isDarwin) pkgs.buildPackages.bear
-              ++ lib.optional
-                (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform)
-                pkgs.buildPackages.clang-tools
-              # We want changelog-d in the shell even if the current build doesn't need it
-              ++ lib.optional (officialRelease || ! buildUnreleasedNotes) changelog-d
-              ;
-
-            buildInputs = buildDeps ++ propagatedDeps
-              ++ awsDeps ++ checkDeps ++ internalApiDocsDeps;
-
-            configureFlags = configureFlags
-              ++ testConfigureFlags ++ internalApiDocsConfigureFlags
-              ++ lib.optional (!canRunInstalled) "--disable-doc-gen";
-
-            enableParallelBuilding = true;
-
-            installFlags = "sysconfdir=$(out)/etc";
-
-            shellHook =
-              ''
+              shellHook = ''
                PATH=$prefix/bin:$PATH
                unset PYTHONPATH
                export MANPATH=$out/share/man:$MANPATH
@ -666,7 +453,7 @@
                # Make bash completion work.
                XDG_DATA_DIRS+=:$out/share
              '';
-          };
+            });
        in
        forAllSystems (system:
          let
--- a/meson.build
+++ b/meson.build
@ -0,0 +1,222 @@
+project('lix', 'cpp',
+  version : run_command('bash', '-c', 'echo -n $(cat ./.version)$VERSION_SUFFIX', check : true).stdout().strip(),
+  default_options : [
+    'cpp_std=c++20',
+    'warning_level=1',
+    'debug=true',
+    'optimization=3',
+  ],
+)
+
+cxx = meson.get_compiler('cpp')
+
+host_system = host_machine.cpu_family() + '-' + host_machine.system()
+message('canonical Nix system name:', host_system)
+
+all_sources = { }
+all_deps = { }
+
+deps = [ ]
+configdata = { }
+
+#
+# Dependencies
+#
+
+boehm = dependency('bdw-gc', required : get_option('gc'))
+if boehm.found()
+  deps += boehm
+endif
+configdata += {
+  'HAVE_BOEHMGC': boehm.found().to_int(),
+}
+
+boost = dependency('boost', required : true, modules : ['context', 'coroutine', 'container'])
+deps += boost
+
+cpuid = dependency('libcpuid', 'cpuid', required : get_option('cpuid'))
+configdata += {
+  'HAVE_LIBCPUID': cpuid.found().to_int(),
+  }
+deps += cpuid
+
+seccomp = dependency('libseccomp', 'seccomp', required : get_option('seccomp-sandboxing'))
+configdata += {
+  'HAVE_SECCOMP': seccomp.found().to_int(),
+  }
+
+libarchive = dependency('libarchive', required : true)
+deps += libarchive
+
+brotli = [
+  dependency('libbrotlicommon', required : true),
+  dependency('libbrotlidec', required : true),
+  dependency('libbrotlienc', required : true),
+  ]
+deps += brotli
+
+openssl = dependency('libcrypto', 'openssl', required : true)
+deps += openssl
+
+aws_sdk = dependency('aws-cpp-sdk-core', required : true)
+if aws_sdk.found()
+  # The AWS pkg-config adds -std=c++11.
+  aws_sdk = aws_sdk.partial_dependency(
+    compile_args : false,
+    includes : true,
+    link_args : true,
+    links : true,
+    sources : true,
+  )
+  deps += aws_sdk
+  s = aws_sdk.version().split('.')
+  configdata += {
+    'AWS_VERSION_MAJOR': s[0].to_int(),
+    'AWS_VERSION_MINOR': s[1].to_int(),
+    'AWS_VERSION_PATCH': s[2].to_int(),
+  }
+  aws_sdk_transfer = dependency('aws-cpp-sdk-transfer', required : true).partial_dependency(
+    compile_args : false,
+    includes : true,
+    link_args : true,
+    links : true,
+    sources : true,
+  )
+endif
+aws_s3 = dependency('aws-cpp-sdk-s3', required : true)
+if aws_s3.found()
+  # The AWS pkg-config adds -std=c++11.
+  aws_s3 = aws_s3.partial_dependency(
+    compile_args : false,
+    includes : true,
+    link_args : true,
+    links : true,
+    sources : true,
+  )
+  deps += aws_s3
+endif
+
+sqlite = dependency('sqlite3', 'sqlite', version : '>=3.6.19', required : true)
+deps += sqlite
+
+sodium = dependency('sodium', 'libsodium', required : true)
+deps += sodium
+
+curl = dependency('libcurl', 'curl', required : true)
+deps += curl
+
+editline = dependency('libeditline', 'editline', version : '>=1.14', required : true)
+deps += editline
+
+lowdown = dependency('lowdown', version : '>=0.9.0', required : true)
+deps += lowdown
+
+#
+# Build-time tools
+#
+bash = find_program('bash')
+lsof = find_program('lsof')
+
+# This is how Nix does generated headers...
+# FIXME(Qyriad): do we really need to use the shell for this?
+gen_header = generator(
+  bash,
+  arguments : [
+    '-c',
+    'echo \'R"foo(\' | cat - @INPUT@ && echo \')foo"\'',
+  ],
+  capture : true,
+  output : '@PLAINNAME@.gen.hh',
+)
+
+#
+# Configuration
+#
+
+# FIXME(Qyriad): at least do this in the build directory
+run_command('ln', '-s', 'bla', 'tmp_link', check : true)
+can_link_symlink = run_command('ln', 'tmp_link', 'tmp_link2', check : false).returncode() == 0
+run_command('rm', '-f', 'tmp_link', 'tmp_link2', check : true)
+message('possible to create a link to a symlink:', can_link_symlink)
+configdata += { 'CAN_LINK_SYMLINK': can_link_symlink.to_int() }
+
+check_headers = [
+  # I can't use dictionaries here as they can only contain identifier-strings.
+  ['aws/s3/S3Client.h', aws_s3]
+]
+
+foreach headerspec : check_headers
+  key = headerspec[0]
+  value = headerspec[1]
+  define_name = 'HAVE_' + key.underscorify().to_upper()
+  define_value = cxx.check_header(key, dependencies : value).to_int()
+  configdata += { define_name: define_value }
+endforeach
+
+check_funcs = [
+  'lchown',
+  'lutimes',
+  'pipe2',
+  'posix_fallocate',
+  'statvfs',
+  'strsignal',
+  'sysconf',
+]
+
+foreach funcspec : check_funcs
+  define_name = 'HAVE_' + funcspec.underscorify().to_upper()
+  define_value = cxx.has_function(funcspec).to_int()
+  configdata += {
+    define_name: define_value,
+  }
+endforeach
+
+has_pubsetbuf = cxx.compiles('''
+  #include <iostream>
+  using namespace std;
+  static char buf[1024];
+  decltype(cerr.rdbuf()->pubsetbuf(buf, sizeof(buf))) _;
+''')
+message('have function "\x1b[1mstd::basic_streambuf::pubsetbuf\x1b[0m" :', has_pubsetbuf)
+configdata += {
+  'HAVE_PUBSETBUF': has_pubsetbuf.to_int(),
+}
+
+configdata += {
+  'ENABLE_S3': aws_s3.found().to_int(),
+}
+
+configure_file(
+  configuration : {
+    'PACKAGE_NAME': '"' + meson.project_name() + '"',
+    'PACKAGE_VERSION': '"' + meson.project_version() + '"',
+    'PACKAGE_TARNAME': '"' + meson.project_name() + '"',
+    'PACKAGE_STRING': '"' + meson.project_name() + ' ' + meson.project_version() + '"',
+    'HAVE_STRUCT_DIRENT_D_TYPE': 1, # FIXME: actually check this for solaris
+    'SYSTEM': '"' + host_system + '"',
+  } + configdata,
+  output : 'config.h',
+)
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # I would love to remove this.
+  '-include', 'config.h',
+  # TODO(Qyriad): would love to remove these
+  '-Wno-deprecated-declarations',
+  '-Wno-unused-parameter',
+  '-Wno-missing-field-initializers',
+  '-Wno-deprecated-copy',
+  '-pthread',
+  #'-fPIC',
+  language : 'cpp',
+)
+
+# FIXME(Qyriad): only if not Darwin, Solaris, or FreeBSD
+# (...so only if Linux?)
+add_project_link_arguments(
+  '-Wl,--no-copy-dt-needed-entries',
+  language : 'cpp',
+)
+
+subdir('src')
--- a/meson.options
+++ b/meson.options
@ -0,0 +1,24 @@
+# vim: filetype=meson
+option('gc', type : 'feature',
+  description : 'enable garbage collection in the Nix expression evaluator (requires Boehm GC)',
+)
+# TODO(Qyriad): is this feature maintained?
+option('embedded-sandbox-shell', type : 'feature',
+  description : 'include the sandbox shell in the Nix bindary',
+)
+
+option('cpuid', type : 'feature',
+  description : 'determine microarchitecture levels with libcpuid (only relevant on x86_64)',
+)
+
+option('seccomp-sandboxing', type : 'feature',
+  description : 'build support for seccomp sandboxing (recommended unless your arch doesn\'t support libseccomp, only relevant on Linux)',
+)
+
+option('store-dir', type : 'string', value : '/nix/store',
+  description : 'path of the Nix store',
+)
+
+option('sandbox-shell', type : 'string',
+  description : 'path to a statically-linked shell to use as /bin/sh in sandboxes (usually busybox)',
+)
--- a/package.nix
+++ b/package.nix
@ -0,0 +1,258 @@
+{
+  pkgs,
+  lib,
+  stdenv,
+  autoconf-archive,
+  autoreconfHook,
+  aws-sdk-cpp,
+  boehmgc,
+  nlohmann_json,
+  bison,
+  changelog-d,
+  cmake,
+  boost,
+  brotli,
+  bzip2,
+  curl,
+  editline,
+  fileset,
+  flex,
+  git,
+  gtest,
+  jq,
+  libarchive,
+  libcpuid,
+  libseccomp,
+  libsodium,
+  lsof,
+  lowdown,
+  mdbook,
+  mdbook-linkcheck,
+  mercurial,
+  meson,
+  ninja,
+  openssl,
+  pkg-config,
+  rapidcheck,
+  sqlite,
+  util-linuxMinimal ? utillinuxMinimal,
+  utillinuxMinimal ? null,
+  xz,
+
+  busybox-sandbox-shell,
+
+  pname ? "nix",
+  versionSuffix ? "",
+  officialRelease ? true,
+  # Set to true to build the release notes for the next release.
+  buildUnreleasedNotes ? false,
+
+  # Not a real argument, just the only way to approximate let-binding some
+  # stuff for argument defaults.
+  __forDefaults ? {
+    canRunInstalled = stdenv.buildPlatform.canExecute stdenv.hostPlatform;
+  },
+}: let
+  inherit (__forDefaults) canRunInstalled;
+
+  version = lib.fileContents ./.version + versionSuffix;
+
+  aws-sdk-cpp-nix = aws-sdk-cpp.override {
+    apis = [ "s3" "transfer" ];
+    customMemoryManagement = false;
+  };
+
+  testConfigureFlags = [
+    "RAPIDCHECK_HEADERS=${lib.getDev rapidcheck}/extras/gtest/include"
+  ];
+
+  # .gitignore has already been processed, so any changes in it are irrelevant
+  # at this point. It is not represented verbatim for test purposes because
+  # that would interfere with repo semantics.
+  baseFiles = fileset.fileFilter (f: f.name != ".gitignore") ./.;
+
+  configureFiles = fileset.unions [
+    ./.version
+    ./configure.ac
+    ./m4
+    # TODO: do we really need README.md? It doesn't seem used in the build.
+    ./README.md
+  ];
+
+  topLevelBuildFiles = fileset.unions [
+    ./local.mk
+    ./Makefile
+    ./Makefile.config.in
+    ./mk
+  ];
+
+ functionalTestFiles = fileset.unions [
+    ./tests/functional
+    ./tests/unit
+    (fileset.fileFilter (f: lib.strings.hasPrefix "nix-profile" f.name) ./scripts)
+ ];
+
+in stdenv.mkDerivation (finalAttrs: {
+  inherit pname version;
+
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.intersection baseFiles (fileset.unions ([
+      configureFiles
+      topLevelBuildFiles
+      functionalTestFiles
+      ./unit-test-data
+    ] ++ lib.optionals finalAttrs.doBuild [
+      ./boehmgc-coroutine-sp-fallback.diff
+      ./doc
+      ./misc
+      ./precompiled-headers.h
+      ./src
+      ./COPYING
+      ./scripts/local.mk
+    ]));
+  };
+
+  VERSION_SUFFIX = versionSuffix;
+
+  outputs = [ "out" ]
+    ++ lib.optionals finalAttrs.doBuild [ "dev" "doc" ];
+
+  # dontBuild isn't specified most of the time, where it is implicitly false.
+  doBuild = !(finalAttrs.dontBuild or false);
+
+  nativeBuildInputs = [
+    bison
+    flex
+  ] ++ [
+    (lib.getBin lowdown)
+    mdbook
+    mdbook-linkcheck
+    autoconf-archive
+    autoreconfHook
+    pkg-config
+
+    # Tests
+    git
+    mercurial
+    jq
+    cmake
+    meson
+    ninja
+    lsof
+  ] ++ lib.optional stdenv.hostPlatform.isLinux util-linuxMinimal
+    ++ lib.optional (!officialRelease && buildUnreleasedNotes) changelog-d;
+
+  buildInputs = [
+    curl
+    bzip2
+    xz
+    brotli
+    editline
+    openssl
+    sqlite
+    libarchive
+    boost
+    lowdown
+    libsodium
+  ]
+    ++ lib.optionals stdenv.isLinux [ libseccomp ]
+    ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid
+    # There have been issues building these dependencies
+    ++ lib.optional (stdenv.hostPlatform == stdenv.buildPlatform) aws-sdk-cpp-nix
+  ;
+
+  checkInputs = [
+    gtest
+    rapidcheck
+  ];
+
+  propagatedBuildInputs = [
+    boehmgc
+    nlohmann_json
+  ];
+
+  disallowedReferences = [
+    boost
+  ];
+
+  # Needed for Meson to find Boost.
+  # https://github.com/NixOS/nixpkgs/issues/86131.
+  env.BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
+  env.BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
+
+  preConfigure = lib.optionalString (finalAttrs.doBuild && (! stdenv.hostPlatform.isStatic)) ''
+      # Copy libboost_context so we don't get all of Boost in our closure.
+      # https://github.com/NixOS/nixpkgs/issues/45462
+      mkdir -p $out/lib
+      cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
+      rm -f $out/lib/*.a
+      ${lib.optionalString stdenv.hostPlatform.isLinux ''
+        chmod u+w $out/lib/*.so.*
+        patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
+      ''}
+      ${lib.optionalString stdenv.hostPlatform.isDarwin ''
+        for LIB in $out/lib/*.dylib; do
+          chmod u+w $LIB
+          install_name_tool -id $LIB $LIB
+          install_name_tool -delete_rpath ${boost}/lib/ $LIB || true
+        done
+        install_name_tool -change ${boost}/lib/libboost_system.dylib $out/lib/libboost_system.dylib $out/lib/libboost_thread.dylib
+      ''}
+  '';
+
+  configureFlags = lib.optionals stdenv.isLinux [
+    "--with-boost=${boost}/lib"
+    "--with-sandbox-shell=${busybox-sandbox-shell}/bin/busybox"
+  ] ++ lib.optionals (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) [
+    "LDFLAGS=-fuse-ld=gold"
+  ] ++ [ "--sysconfdir=/etc" ]
+    ++ lib.optional stdenv.hostPlatform.isStatic "--enable-embedded-sandbox-shell"
+    ++ [ (lib.enableFeature finalAttrs.doCheck "tests") ]
+    ++ lib.optionals finalAttrs.doCheck testConfigureFlags
+    ++ lib.optional (!canRunInstalled) "--disable-doc-gen"
+  ;
+
+  enableParallelBuilding = true;
+
+  makeFlags = "profiledir=$(out)/etc/profile.d PRECOMPILE_HEADERS=1";
+
+  doCheck = true;
+
+  installFlags = "sysconfdir=$(out)/etc";
+
+  postInstall = ''
+      mkdir -p $doc/nix-support
+      echo "doc manual $doc/share/doc/nix/manual" >> $doc/nix-support/hydra-build-products
+      ${lib.optionalString stdenv.hostPlatform.isStatic ''
+      mkdir -p $out/nix-support
+      echo "file binary-dist $out/bin/nix" >> $out/nix-support/hydra-build-products
+      ''}
+      ${lib.optionalString stdenv.isDarwin ''
+      install_name_tool \
+        -change ${boost}/lib/libboost_context.dylib \
+        $out/lib/libboost_context.dylib \
+        $out/lib/libnixutil.dylib
+      ''}
+  '';
+
+  doInstallCheck = finalAttrs.doCheck;
+  installCheckFlags = "sysconfdir=$(out)/etc";
+  installCheckTarget = "installcheck"; # work around buggy detection in stdenv
+
+  preInstallCheck = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
+  '';
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic && finalAttrs.doBuild;
+
+  strictDeps = true;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  meta.platforms = lib.platforms.unix;
+
+  passthru.perl-bindings = pkgs.callPackage ./perl {
+    inherit fileset stdenv;
+  };
+})
--- a/src/libcmd/meson.build
+++ b/src/libcmd/meson.build
@ -0,0 +1,35 @@
+libcmd_sources = files(
+  'built-path.cc',
+  'command-installable-value.cc',
+  'command.cc',
+  'common-eval-args.cc',
+  'editor-for.cc',
+  'installable-attr-path.cc',
+  'installable-derived-path.cc',
+  'installable-flake.cc',
+  'installable-value.cc',
+  'installables.cc',
+  'legacy.cc',
+  'markdown.cc',
+  'repl.cc',
+)
+
+libcmd = library(
+  'nixcmd',
+  libcmd_sources,
+  dependencies : [
+    liblixutil,
+    liblixstore,
+    liblixexpr,
+    liblixfetchers,
+    liblixmain,
+    boehm,
+    editline,
+    lowdown,
+  ],
+)
+
+liblixcmd = declare_dependency(
+  include_directories : '.',
+  link_with : libcmd,
+)
--- a/src/libexpr/c/meson.build
+++ b/src/libexpr/c/meson.build
@ -0,0 +1,31 @@
+pkg = import('pkgconfig')
+
+libexprc_sources = files(
+  'nix_api_expr.cc',
+  'nix_api_external.cc',
+  'nix_api_value.cc',
+)
+
+all_sources += {
+  'libexprc': libexprc_sources
+}
+
+libexprc = library(
+  'nix-expr-c',
+  libexprc_sources,
+  dependencies : [
+    liblixutil,
+    liblixstore,
+    liblixexpr,
+    liblixutilc,
+    liblixstorec,
+    boehm,
+  ],
+)
+
+pkg.generate(libexprc, requires: [ 'nix-store-c' ])
+
+liblixexprc = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libexprc,
+)
--- a/src/libexpr/c/nix_api_expr.cc
+++ b/src/libexpr/c/nix_api_expr.cc
@ -0,0 +1,178 @@
+#include <cstring>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+
+#include "config.hh"
+#include "eval.hh"
+#include "globals.hh"
+#include "util.hh"
+
+#include "nix_api_expr.h"
+#include "nix_api_expr_internal.h"
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+
+#ifdef HAVE_BOEHMGC
+#include <mutex>
+#define GC_INCLUDE_NEW 1
+#include "gc_cpp.h"
+#endif
+
+nix_err nix_libexpr_init(nix_c_context * context)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    {
+        auto ret = nix_libutil_init(context);
+        if (ret != NIX_OK)
+            return ret;
+    }
+    {
+        auto ret = nix_libstore_init(context);
+        if (ret != NIX_OK)
+            return ret;
+    }
+    try {
+        nix::initGC();
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_expr_eval_from_string(
+    nix_c_context * context, EvalState * state, const char * expr, const char * path, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::Expr * parsedExpr = state->state.parseExprFromString(expr, state->state.rootPath(nix::CanonPath(path)));
+        state->state.eval(parsedExpr, *(nix::Value *) value);
+        state->state.forceValue(*(nix::Value *) value, nix::noPos);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_value_call(nix_c_context * context, EvalState * state, Value * fn, Value * arg, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        state->state.callFunction(*(nix::Value *) fn, *(nix::Value *) arg, *(nix::Value *) value, nix::noPos);
+        state->state.forceValue(*(nix::Value *) value, nix::noPos);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_value_force(nix_c_context * context, EvalState * state, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        state->state.forceValue(*(nix::Value *) value, nix::noPos);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_value_force_deep(nix_c_context * context, EvalState * state, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        state->state.forceValueDeep(*(nix::Value *) value);
+    }
+    NIXC_CATCH_ERRS
+}
+
+EvalState * nix_state_create(nix_c_context * context, const char ** searchPath_c, Store * store)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::Strings searchPath;
+        if (searchPath_c != nullptr)
+            for (size_t i = 0; searchPath_c[i] != nullptr; i++)
+                searchPath.push_back(searchPath_c[i]);
+
+        return new EvalState{nix::EvalState(nix::SearchPath::parse(searchPath), store->ptr)};
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+void nix_state_free(EvalState * state)
+{
+    delete state;
+}
+
+#ifdef HAVE_BOEHMGC
+std::unordered_map<
+    const void *,
+    unsigned int,
+    std::hash<const void *>,
+    std::equal_to<const void *>,
+    traceable_allocator<std::pair<const void * const, unsigned int>>>
+    nix_refcounts;
+
+std::mutex nix_refcount_lock;
+
+nix_err nix_gc_incref(nix_c_context * context, const void * p)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        std::scoped_lock lock(nix_refcount_lock);
+        auto f = nix_refcounts.find(p);
+        if (f != nix_refcounts.end()) {
+            f->second++;
+        } else {
+            nix_refcounts[p] = 1;
+        }
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_gc_decref(nix_c_context * context, const void * p)
+{
+
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        std::scoped_lock lock(nix_refcount_lock);
+        auto f = nix_refcounts.find(p);
+        if (f != nix_refcounts.end()) {
+            if (--f->second == 0)
+                nix_refcounts.erase(f);
+        } else
+            throw std::runtime_error("nix_gc_decref: object was not referenced");
+    }
+    NIXC_CATCH_ERRS
+}
+
+void nix_gc_now()
+{
+    GC_gcollect();
+}
+
+#else
+void nix_gc_incref(nix_c_context * context, const void *)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    return NIX_OK;
+}
+void nix_gc_decref(nix_c_context * context, const void *)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    return NIX_OK;
+}
+void nix_gc_now() {}
+#endif
+
+void nix_gc_register_finalizer(void * obj, void * cd, void (*finalizer)(void * obj, void * cd))
+{
+#ifdef HAVE_BOEHMGC
+    GC_REGISTER_FINALIZER(obj, finalizer, cd, 0, 0);
+#endif
+}
--- a/src/libexpr/c/nix_api_expr.h
+++ b/src/libexpr/c/nix_api_expr.h
@ -0,0 +1,213 @@
+#ifndef NIX_API_EXPR_H
+#define NIX_API_EXPR_H
+/** @defgroup libexpr libexpr
+ * @brief Bindings to the Nix language evaluator
+ *
+ * Example (without error handling):
+ * @code{.c}
+ * int main() {
+ *    nix_libexpr_init(NULL);
+ *
+ *    Store* store = nix_store_open(NULL, "dummy", NULL);
+ *    EvalState* state = nix_state_create(NULL, NULL, store); // empty nix path
+ *    Value *value = nix_alloc_value(NULL, state);
+ *
+ *    nix_expr_eval_from_string(NULL, state, "builtins.nixVersion", ".", value);
+ *    nix_value_force(NULL, state, value);
+ *    printf("nix version: %s\n", nix_get_string(NULL, value));
+ *
+ *    nix_gc_decref(NULL, value);
+ *    nix_state_free(state);
+ *    nix_store_free(store);
+ *    return 0;
+ *    }
+ * @endcode
+ * @{
+ */
+/** @file
+ * @brief Main entry for the libexpr C bindings
+ */
+
+#include "nix_api_store.h"
+#include "nix_api_util.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+// cffi start
+
+// Type definitions
+/**
+ * @brief Represents a state of the Nix language evaluator.
+ *
+ * Multiple states can be created for multi-threaded
+ * operation.
+ * @struct EvalState
+ * @see nix_state_create
+ */
+typedef struct EvalState EvalState; // nix::EvalState
+/**
+ * @brief Represents a value in the Nix language.
+ *
+ * Owned by the garbage collector.
+ * @struct Value
+ * @see value_manip
+ */
+typedef void Value; // nix::Value
+
+// Function prototypes
+/**
+ * @brief Initialize the Nix language evaluator.
+ *
+ * This function must be called at least once,
+ * at some point before constructing a EvalState for the first time.
+ * This function can be called multiple times, and is idempotent.
+ *
+ * @param[out] context Optional, stores error information
+ * @return NIX_OK if the initialization was successful, an error code otherwise.
+ */
+nix_err nix_libexpr_init(nix_c_context * context);
+
+/**
+ * @brief Parses and evaluates a Nix expression from a string.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] state The state of the evaluation.
+ * @param[in] expr The Nix expression to parse.
+ * @param[in] path The file path to associate with the expression.
+ * This is required for expressions that contain relative paths (such as `./.`) that are resolved relative to the given
+ * directory.
+ * @param[out] value The result of the evaluation. You must allocate this
+ * yourself.
+ * @return NIX_OK if the evaluation was successful, an error code otherwise.
+ */
+nix_err nix_expr_eval_from_string(
+    nix_c_context * context, EvalState * state, const char * expr, const char * path, Value * value);
+
+/**
+ * @brief Calls a Nix function with an argument.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] state The state of the evaluation.
+ * @param[in] fn The Nix function to call.
+ * @param[in] arg The argument to pass to the function.
+ * @param[out] value The result of the function call.
+ * @return NIX_OK if the function call was successful, an error code otherwise.
+ */
+nix_err nix_value_call(nix_c_context * context, EvalState * state, Value * fn, Value * arg, Value * value);
+
+/**
+ * @brief Forces the evaluation of a Nix value.
+ *
+ * The Nix interpreter is lazy, and not-yet-evaluated Values can be
+ * of type NIX_TYPE_THUNK instead of their actual value.
+ *
+ * This function converts these Values into their final type.
+ *
+ * @note You don't need this function for basic API usage, since all functions
+ * that return a value call it for you. The only place you will see a
+ * NIX_TYPE_THUNK is in the arguments that are passed to a PrimOp function
+ * you supplied to nix_alloc_primop.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] state The state of the evaluation.
+ * @param[in,out] value The Nix value to force.
+ * @post value is not of type NIX_TYPE_THUNK
+ * @return NIX_OK if the force operation was successful, an error code
+ * otherwise.
+ */
+nix_err nix_value_force(nix_c_context * context, EvalState * state, Value * value);
+
+/**
+ * @brief Forces the deep evaluation of a Nix value.
+ *
+ * Recursively calls nix_value_force
+ *
+ * @see nix_value_force
+ * @warning Calling this function on a recursive data structure will cause a
+ * stack overflow.
+ * @param[out] context Optional, stores error information
+ * @param[in] state The state of the evaluation.
+ * @param[in,out] value The Nix value to force.
+ * @return NIX_OK if the deep force operation was successful, an error code
+ * otherwise.
+ */
+nix_err nix_value_force_deep(nix_c_context * context, EvalState * state, Value * value);
+
+/**
+ * @brief Create a new Nix language evaluator state.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] searchPath Array of strings corresponding to entries in NIX_PATH.
+ * @param[in] store The Nix store to use.
+ * @return A new Nix state or NULL on failure.
+ */
+EvalState * nix_state_create(nix_c_context * context, const char ** searchPath, Store * store);
+
+/**
+ * @brief Frees a Nix state.
+ *
+ * Does not fail.
+ *
+ * @param[in] state The state to free.
+ */
+void nix_state_free(EvalState * state);
+
+/** @addtogroup GC
+ * @brief Reference counting and garbage collector operations
+ *
+ * The Nix language evaluator uses a garbage collector. To ease C interop, we implement
+ * a reference counting scheme, where objects will be deallocated
+ * when there are no references from the Nix side, and the reference count kept
+ * by the C API reaches `0`.
+ *
+ * Functions returning a garbage-collected object will automatically increase
+ * the refcount for you. You should make sure to call `nix_gc_decref` when
+ * you're done with a value returned by the evaluator.
+ * @{
+ */
+/**
+ * @brief Increment the garbage collector reference counter for the given object.
+ *
+ * The Nix language evaluator C API keeps track of alive objects by reference counting.
+ * When you're done with a refcounted pointer, call nix_gc_decref().
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] object The object to keep alive
+ */
+nix_err nix_gc_incref(nix_c_context * context, const void * object);
+/**
+ * @brief Decrement the garbage collector reference counter for the given object
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] object The object to stop referencing
+ */
+nix_err nix_gc_decref(nix_c_context * context, const void * object);
+
+/**
+ * @brief Trigger the garbage collector manually
+ *
+ * You should not need to do this, but it can be useful for debugging.
+ */
+void nix_gc_now();
+
+/**
+ * @brief Register a callback that gets called when the object is garbage
+ * collected.
+ * @note Objects can only have a single finalizer. This function overwrites existing values
+ * silently.
+ * @param[in] obj the object to watch
+ * @param[in] cd the data to pass to the finalizer
+ * @param[in] finalizer the callback function, called with obj and cd
+ */
+void nix_gc_register_finalizer(void * obj, void * cd, void (*finalizer)(void * obj, void * cd));
+
+/** @} */
+// cffi end
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
+
+#endif // NIX_API_EXPR_H
--- a/src/libexpr/c/nix_api_expr_internal.h
+++ b/src/libexpr/c/nix_api_expr_internal.h
@ -0,0 +1,64 @@
+#ifndef NIX_API_EXPR_INTERNAL_H
+#define NIX_API_EXPR_INTERNAL_H
+
+#include "eval.hh"
+#include "attr-set.hh"
+#include "nix_api_value.h"
+
+class CListBuilder
+{
+private:
+    std::vector<nix::Value *> values;
+
+public:
+    CListBuilder(size_t capacity)
+    {
+        values.reserve(capacity);
+    }
+
+    void push_back(nix::Value * value)
+    {
+        values.push_back(value);
+    }
+
+    Value * finish(nix::EvalState * state, nix::Value * list)
+    {
+        state->mkList(*list, values.size());
+        for (size_t n = 0; n < list->listSize(); ++n) {
+            list->listElems()[n] = values[n];
+        }
+        return list;
+    }
+};
+
+struct EvalState
+{
+    nix::EvalState state;
+};
+
+struct BindingsBuilder
+{
+    nix::BindingsBuilder builder;
+};
+
+struct ListBuilder
+{
+    CListBuilder builder;
+};
+
+struct nix_string_return
+{
+    std::string str;
+};
+
+struct nix_printer
+{
+    std::ostream & s;
+};
+
+struct nix_string_context
+{
+    nix::NixStringContext & ctx;
+};
+
+#endif // NIX_API_EXPR_INTERNAL_H
--- a/src/libexpr/c/nix_api_external.cc
+++ b/src/libexpr/c/nix_api_external.cc
@ -0,0 +1,198 @@
+#include "attr-set.hh"
+#include "config.hh"
+#include "eval.hh"
+#include "gc/gc.h"
+#include "globals.hh"
+#include "value.hh"
+
+#include "nix_api_expr.h"
+#include "nix_api_expr_internal.h"
+#include "nix_api_external.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_value.h"
+#include "value/context.hh"
+
+#include <nlohmann/json.hpp>
+
+#ifdef HAVE_BOEHMGC
+#define GC_INCLUDE_NEW 1
+#include "gc_cpp.h"
+#endif
+
+void nix_set_string_return(nix_string_return * str, const char * c)
+{
+    str->str = c;
+}
+
+nix_err nix_external_print(nix_c_context * context, nix_printer * printer, const char * c)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        printer->s << c;
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_external_add_string_context(nix_c_context * context, nix_string_context * ctx, const char * c)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto r = nix::NixStringContextElem::parse(c);
+        ctx->ctx.insert(r);
+    }
+    NIXC_CATCH_ERRS
+}
+
+class NixCExternalValue : public nix::ExternalValueBase
+{
+    NixCExternalValueDesc & desc;
+    void * v;
+
+public:
+    NixCExternalValue(NixCExternalValueDesc & desc, void * v)
+        : desc(desc)
+        , v(v){};
+    void * get_ptr()
+    {
+        return v;
+    }
+    /**
+     * Print out the value
+     */
+    virtual std::ostream & print(std::ostream & str) const override
+    {
+        nix_printer p{str};
+        desc.print(v, &p);
+        return str;
+    }
+
+    /**
+     * Return a simple string describing the type
+     */
+    virtual std::string showType() const override
+    {
+        nix_string_return res;
+        desc.showType(v, &res);
+        return std::move(res.str);
+    }
+
+    /**
+     * Return a string to be used in builtins.typeOf
+     */
+    virtual std::string typeOf() const override
+    {
+        nix_string_return res;
+        desc.typeOf(v, &res);
+        return std::move(res.str);
+    }
+
+    /**
+     * Coerce the value to a string.
+     */
+    virtual std::string coerceToString(
+        nix::EvalState & state,
+        const nix::PosIdx & pos,
+        nix::NixStringContext & context,
+        bool copyMore,
+        bool copyToStore) const override
+    {
+        if (!desc.coerceToString) {
+            return nix::ExternalValueBase::coerceToString(state, pos, context, copyMore, copyToStore);
+        }
+        nix_string_context ctx{context};
+        nix_string_return res{""};
+        // todo: pos, errors
+        desc.coerceToString(v, &ctx, copyMore, copyToStore, &res);
+        if (res.str.empty()) {
+            return nix::ExternalValueBase::coerceToString(state, pos, context, copyMore, copyToStore);
+        }
+        return std::move(res.str);
+    }
+
+    /**
+     * Compare to another value of the same type.
+     */
+    virtual bool operator==(const ExternalValueBase & b) const override
+    {
+        if (!desc.equal) {
+            return false;
+        }
+        auto r = dynamic_cast<const NixCExternalValue *>(&b);
+        if (!r)
+            return false;
+        return desc.equal(v, r->v);
+    }
+
+    /**
+     * Print the value as JSON.
+     */
+    virtual nlohmann::json printValueAsJSON(
+        nix::EvalState & state, bool strict, nix::NixStringContext & context, bool copyToStore = true) const override
+    {
+        if (!desc.printValueAsJSON) {
+            return nix::ExternalValueBase::printValueAsJSON(state, strict, context, copyToStore);
+        }
+        nix_string_context ctx{context};
+        nix_string_return res{""};
+        desc.printValueAsJSON(v, (EvalState *) &state, strict, &ctx, copyToStore, &res);
+        if (res.str.empty()) {
+            return nix::ExternalValueBase::printValueAsJSON(state, strict, context, copyToStore);
+        }
+        return nlohmann::json::parse(res.str);
+    }
+
+    /**
+     * Print the value as XML.
+     */
+    virtual void printValueAsXML(
+        nix::EvalState & state,
+        bool strict,
+        bool location,
+        nix::XMLWriter & doc,
+        nix::NixStringContext & context,
+        nix::PathSet & drvsSeen,
+        const nix::PosIdx pos) const override
+    {
+        if (!desc.printValueAsXML) {
+            return nix::ExternalValueBase::printValueAsXML(state, strict, location, doc, context, drvsSeen, pos);
+        }
+        nix_string_context ctx{context};
+        desc.printValueAsXML(
+            v, (EvalState *) &state, strict, location, &doc, &ctx, &drvsSeen,
+            *reinterpret_cast<const uint32_t *>(&pos));
+    }
+
+    virtual ~NixCExternalValue() override{};
+};
+
+ExternalValue * nix_create_external_value(nix_c_context * context, NixCExternalValueDesc * desc, void * v)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto ret = new
+#ifdef HAVE_BOEHMGC
+            (GC)
+#endif
+                NixCExternalValue(*desc, v);
+        nix_gc_incref(nullptr, ret);
+        return (ExternalValue *) ret;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+void * nix_get_external_value_content(nix_c_context * context, ExternalValue * b)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto r = dynamic_cast<NixCExternalValue *>((nix::ExternalValueBase *) b);
+        if (r)
+            return r->get_ptr();
+        return nullptr;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
--- a/src/libexpr/c/nix_api_external.h
+++ b/src/libexpr/c/nix_api_external.h
@ -0,0 +1,196 @@
+#ifndef NIX_API_EXTERNAL_H
+#define NIX_API_EXTERNAL_H
+/** @ingroup libexpr
+ * @addtogroup Externals
+ * @brief Deal with external values
+ * @{
+ */
+/** @file
+ * @brief libexpr C bindings dealing with external values
+ */
+
+#include "nix_api_expr.h"
+#include "nix_api_util.h"
+#include "nix_api_value.h"
+#include "stdbool.h"
+#include "stddef.h"
+#include "stdint.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+// cffi start
+
+/**
+ * @brief Represents a string owned by the Nix language evaluator.
+ * @see nix_set_owned_string
+ */
+typedef struct nix_string_return nix_string_return;
+/**
+ * @brief Wraps a stream that can output multiple string pieces.
+ */
+typedef struct nix_printer nix_printer;
+/**
+ * @brief A list of string context items
+ */
+typedef struct nix_string_context nix_string_context;
+
+/**
+ * @brief Sets the contents of a nix_string_return
+ *
+ * Copies the passed string.
+ * @param[out] str the nix_string_return to write to
+ * @param[in]  c   The string to copy
+ */
+void nix_set_string_return(nix_string_return * str, const char * c);
+
+/**
+ * Print to the nix_printer
+ *
+ * @param[out] context Optional, stores error information
+ * @param printer The nix_printer to print to
+ * @param[in] str The string to print
+ * @returns NIX_OK if everything worked
+ */
+nix_err nix_external_print(nix_c_context * context, nix_printer * printer, const char * str);
+
+/**
+ * Add string context to the nix_string_context object
+ * @param[out] context Optional, stores error information
+ * @param[out] string_context The nix_string_context to add to
+ * @param[in] c The context string to add
+ * @returns NIX_OK if everything worked
+ */
+nix_err nix_external_add_string_context(nix_c_context * context, nix_string_context * string_context, const char * c);
+
+/**
+ * @brief Definition for a class of external values
+ *
+ * Create and implement one of these, then pass it to nix_create_external_value
+ * Make sure to keep it alive while the external value lives.
+ *
+ * Optional functions can be set to NULL
+ *
+ * @see nix_create_external_value
+ */
+typedef struct NixCExternalValueDesc
+{
+    /**
+     * @brief Called when printing the external value
+     *
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[out] printer The printer to print to, pass to nix_external_print
+     */
+    void (*print)(void * self, nix_printer * printer);
+    /**
+     * @brief Called on :t
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[out] res the return value
+     */
+    void (*showType)(void * self, nix_string_return * res);
+    /**
+     * @brief Called on `builtins.typeOf`
+     * @param self the void* passed to nix_create_external_value
+     * @param[out] res the return value
+     */
+    void (*typeOf)(void * self, nix_string_return * res);
+    /**
+     * @brief Called on "${str}" and builtins.toString.
+     *
+     * The latter with coerceMore=true
+     * Optional, the default is to throw an error.
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[out] c writable string context for the resulting string
+     * @param[in] coerceMore boolean, try to coerce to strings in more cases
+     * instead of throwing an error
+     * @param[in] copyToStore boolean, whether to copy referenced paths to store
+     * or keep them as-is
+     * @param[out] res the return value. Not touching this, or setting it to the
+     * empty string, will make the conversion throw an error.
+     */
+    void (*coerceToString)(
+        void * self, nix_string_context * c, int coerceMore, int copyToStore, nix_string_return * res);
+    /**
+     * @brief Try to compare two external values
+     *
+     * Optional, the default is always false.
+     * If the other object was not a Nix C external value, this comparison will
+     * also return false
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[in] other the void* passed to the other object's
+     * nix_create_external_value
+     * @returns true if the objects are deemed to be equal
+     */
+    int (*equal)(void * self, void * other);
+    /**
+     * @brief Convert the external value to json
+     *
+     * Optional, the default is to throw an error
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[in] state The evaluator state
+     * @param[in] strict boolean Whether to force the value before printing
+     * @param[out] c writable string context for the resulting string
+     * @param[in] copyToStore whether to copy referenced paths to store or keep
+     * them as-is
+     * @param[out] res the return value. Gets parsed as JSON. Not touching this,
+     * or setting it to the empty string, will make the conversion throw an error.
+     */
+    void (*printValueAsJSON)(
+        void * self, EvalState *, bool strict, nix_string_context * c, bool copyToStore, nix_string_return * res);
+    /**
+     * @brief Convert the external value to XML
+     *
+     * Optional, the default is to throw an error
+     * @todo The mechanisms for this call are incomplete. There are no C
+     *       bindings to work with XML, pathsets and positions.
+     * @param[in] self the void* passed to nix_create_external_value
+     * @param[in] state The evaluator state
+     * @param[in] strict boolean Whether to force the value before printing
+     * @param[in] location boolean Whether to include position information in the
+     * xml
+     * @param[out] doc XML document to output to
+     * @param[out] c writable string context for the resulting string
+     * @param[in,out] drvsSeen a path set to avoid duplicating derivations
+     * @param[in] pos The position of the call.
+     */
+    void (*printValueAsXML)(
+        void * self,
+        EvalState *,
+        int strict,
+        int location,
+        void * doc,
+        nix_string_context * c,
+        void * drvsSeen,
+        int pos);
+} NixCExternalValueDesc;
+
+/**
+ * @brief Create an external value, that can be given to nix_init_external
+ *
+ * Owned by the GC. Use nix_gc_decref when you're done with the pointer.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] desc a NixCExternalValueDesc, you should keep this alive as long
+ * as the ExternalValue lives
+ * @param[in] v the value to store
+ * @returns external value, owned by the garbage collector
+ * @see nix_init_external
+ */
+ExternalValue * nix_create_external_value(nix_c_context * context, NixCExternalValueDesc * desc, void * v);
+
+/**
+ * @brief Extract the pointer from a nix c external value.
+ * @param[out] context Optional, stores error information
+ * @param[in] b The external value
+ * @returns The pointer, or null if the external value was not from nix c.
+ * @see nix_get_external
+ */
+void * nix_get_external_value_content(nix_c_context * context, ExternalValue * b);
+
+// cffi end
+#ifdef __cplusplus
+}
+#endif
+/** @} */
+
+#endif // NIX_API_EXTERNAL_H
--- a/src/libexpr/c/nix_api_value.cc
+++ b/src/libexpr/c/nix_api_value.cc
@ -0,0 +1,521 @@
+#include "attr-set.hh"
+#include "config.hh"
+#include "eval.hh"
+#include "gc/gc.h"
+#include "globals.hh"
+#include "primops.hh"
+#include "value.hh"
+
+#include "nix_api_expr.h"
+#include "nix_api_expr_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_value.h"
+
+#ifdef HAVE_BOEHMGC
+#define GC_INCLUDE_NEW 1
+#include "gc_cpp.h"
+#endif
+
+// Helper function to throw an exception if value is null
+static const nix::Value & check_value_not_null(const Value * value)
+{
+    if (!value) {
+        throw std::runtime_error("Value is null");
+    }
+    return *((const nix::Value *) value);
+}
+
+static nix::Value & check_value_not_null(Value * value)
+{
+    if (!value) {
+        throw std::runtime_error("Value is null");
+    }
+    return *((nix::Value *) value);
+}
+
+/**
+ * Helper function to convert calls from nix into C API.
+ *
+ * Deals with errors and converts arguments from C++ into C types.
+ */
+static void nix_c_primop_wrapper(
+    PrimOpFun f, void * userdata, nix::EvalState & state, const nix::PosIdx pos, nix::Value ** args, nix::Value & v)
+{
+    nix_c_context ctx;
+    f(userdata, &ctx, (EvalState *) &state, (Value **) args, (Value *) &v);
+    /* TODO: In the future, this should throw different errors depending on the error code */
+    if (ctx.last_err_code != NIX_OK)
+        state.error<nix::EvalError>("Error from builtin function: %s", *ctx.last_err).atPos(pos).debugThrow();
+}
+
+PrimOp * nix_alloc_primop(
+    nix_c_context * context,
+    PrimOpFun fun,
+    int arity,
+    const char * name,
+    const char ** args,
+    const char * doc,
+    void * user_data)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        using namespace std::placeholders;
+        auto p = new
+#ifdef HAVE_BOEHMGC
+            (GC)
+#endif
+                nix::PrimOp{
+                    .name = name,
+                    .args = {},
+                    .arity = (size_t) arity,
+                    .doc = doc,
+                    .fun = std::bind(nix_c_primop_wrapper, fun, user_data, _1, _2, _3, _4)};
+        if (args)
+            for (size_t i = 0; args[i]; i++)
+                p->args.emplace_back(*args);
+        nix_gc_incref(nullptr, p);
+        return (PrimOp *) p;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+nix_err nix_register_primop(nix_c_context * context, PrimOp * primOp)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::RegisterPrimOp r(std::move(*((nix::PrimOp *) primOp)));
+    }
+    NIXC_CATCH_ERRS
+}
+
+Value * nix_alloc_value(nix_c_context * context, EvalState * state)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        Value * res = state->state.allocValue();
+        nix_gc_incref(nullptr, res);
+        return res;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+ValueType nix_get_type(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        using namespace nix;
+        switch (v.type()) {
+        case nThunk:
+            return NIX_TYPE_THUNK;
+        case nInt:
+            return NIX_TYPE_INT;
+        case nFloat:
+            return NIX_TYPE_FLOAT;
+        case nBool:
+            return NIX_TYPE_BOOL;
+        case nString:
+            return NIX_TYPE_STRING;
+        case nPath:
+            return NIX_TYPE_PATH;
+        case nNull:
+            return NIX_TYPE_NULL;
+        case nAttrs:
+            return NIX_TYPE_ATTRS;
+        case nList:
+            return NIX_TYPE_LIST;
+        case nFunction:
+            return NIX_TYPE_FUNCTION;
+        case nExternal:
+            return NIX_TYPE_EXTERNAL;
+        }
+        return NIX_TYPE_NULL;
+    }
+    NIXC_CATCH_ERRS_RES(NIX_TYPE_NULL);
+}
+
+const char * nix_get_typename(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        auto s = nix::showType(v);
+        return strdup(s.c_str());
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+bool nix_get_bool(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nBool);
+        return v.boolean;
+    }
+    NIXC_CATCH_ERRS_RES(false);
+}
+
+const char * nix_get_string(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nString);
+        return v.string.s;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+const char * nix_get_path_string(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nPath);
+        return v._path;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+unsigned int nix_get_list_size(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nList);
+        return v.listSize();
+    }
+    NIXC_CATCH_ERRS_RES(0);
+}
+
+unsigned int nix_get_attrs_size(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nAttrs);
+        return v.attrs->size();
+    }
+    NIXC_CATCH_ERRS_RES(0);
+}
+
+double nix_get_float(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nFloat);
+        return v.fpoint;
+    }
+    NIXC_CATCH_ERRS_RES(NAN);
+}
+
+int64_t nix_get_int(nix_c_context * context, const Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nInt);
+        return v.integer;
+    }
+    NIXC_CATCH_ERRS_RES(0);
+}
+
+ExternalValue * nix_get_external(nix_c_context * context, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nExternal);
+        return (ExternalValue *) v.external;
+    }
+    NIXC_CATCH_ERRS_NULL;
+}
+
+Value * nix_get_list_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int ix)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nList);
+        auto * p = v.listElems()[ix];
+        nix_gc_incref(nullptr, p);
+        state->state.forceValue(*p, nix::noPos);
+        return (Value *) p;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+Value * nix_get_attr_byname(nix_c_context * context, const Value * value, EvalState * state, const char * name)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nAttrs);
+        nix::Symbol s = state->state.symbols.create(name);
+        auto attr = v.attrs->get(s);
+        if (attr) {
+            nix_gc_incref(nullptr, attr->value);
+            state->state.forceValue(*attr->value, nix::noPos);
+            return attr->value;
+        }
+        nix_set_err_msg(context, NIX_ERR_KEY, "missing attribute");
+        return nullptr;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+bool nix_has_attr_byname(nix_c_context * context, const Value * value, EvalState * state, const char * name)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        assert(v.type() == nix::nAttrs);
+        nix::Symbol s = state->state.symbols.create(name);
+        auto attr = v.attrs->get(s);
+        if (attr)
+            return true;
+        return false;
+    }
+    NIXC_CATCH_ERRS_RES(false);
+}
+
+Value *
+nix_get_attr_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int i, const char ** name)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        const nix::Attr & a = (*v.attrs)[i];
+        *name = ((const std::string &) (state->state.symbols[a.name])).c_str();
+        nix_gc_incref(nullptr, a.value);
+        state->state.forceValue(*a.value, nix::noPos);
+        return a.value;
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+const char * nix_get_attr_name_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int i)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        const nix::Attr & a = (*v.attrs)[i];
+        return ((const std::string &) (state->state.symbols[a.name])).c_str();
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+nix_err nix_init_bool(nix_c_context * context, Value * value, bool b)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkBool(b);
+    }
+    NIXC_CATCH_ERRS
+}
+
+// todo string context
+nix_err nix_init_string(nix_c_context * context, Value * value, const char * str)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkString(std::string_view(str));
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_path_string(nix_c_context * context, EvalState * s, Value * value, const char * str)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkPath(s->state.rootPath(nix::CanonPath(str)));
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_float(nix_c_context * context, Value * value, double d)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkFloat(d);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_int(nix_c_context * context, Value * value, int64_t i)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkInt(i);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_null(nix_c_context * context, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkNull();
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_external(nix_c_context * context, Value * value, ExternalValue * val)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        auto r = (nix::ExternalValueBase *) val;
+        v.mkExternal(r);
+    }
+    NIXC_CATCH_ERRS
+}
+
+ListBuilder * nix_make_list_builder(nix_c_context * context, EvalState * state, size_t capacity)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto builder = CListBuilder(capacity);
+        return new
+#if HAVE_BOEHMGC
+            (NoGC)
+#endif
+                ListBuilder{std::move(builder)};
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+nix_err nix_list_builder_insert(nix_c_context * context, ListBuilder * list_builder, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        list_builder->builder.push_back((nix::Value *) value);
+    }
+    NIXC_CATCH_ERRS
+}
+
+void nix_list_builder_free(ListBuilder * bb)
+{
+#if HAVE_BOEHMGC
+    GC_FREE(bb);
+#else
+    delete bb;
+#endif
+}
+
+nix_err nix_make_list(nix_c_context * context, EvalState * s, ListBuilder * list_builder, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        list_builder->builder.finish(&(s->state), &v);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_primop(nix_c_context * context, Value * value, PrimOp * p)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkPrimOp((nix::PrimOp *) p);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_copy_value(nix_c_context * context, Value * value, Value * source)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        auto & s = check_value_not_null(source);
+        v = s;
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_make_attrs(nix_c_context * context, Value * value, BindingsBuilder * b)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        v.mkAttrs(b->builder);
+    }
+    NIXC_CATCH_ERRS
+}
+
+BindingsBuilder * nix_make_bindings_builder(nix_c_context * context, EvalState * state, size_t capacity)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto bb = state->state.buildBindings(capacity);
+        return new
+#if HAVE_BOEHMGC
+            (NoGC)
+#endif
+                BindingsBuilder{std::move(bb)};
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+nix_err nix_bindings_builder_insert(nix_c_context * context, BindingsBuilder * bb, const char * name, Value * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto & v = check_value_not_null(value);
+        nix::Symbol s = bb->builder.state.symbols.create(name);
+        bb->builder.insert(s, &v);
+    }
+    NIXC_CATCH_ERRS
+}
+
+void nix_bindings_builder_free(BindingsBuilder * bb)
+{
+#if HAVE_BOEHMGC
+    GC_FREE((nix::BindingsBuilder *) bb);
+#else
+    delete (nix::BindingsBuilder *) bb;
+#endif
+}
--- a/src/libexpr/c/nix_api_value.h
+++ b/src/libexpr/c/nix_api_value.h
@ -0,0 +1,433 @@
+#ifndef NIX_API_VALUE_H
+#define NIX_API_VALUE_H
+
+/** @addtogroup libexpr
+ * @{
+ */
+/** @file
+ * @brief libexpr C bindings dealing with values
+ */
+
+#include "nix_api_util.h"
+#include "stdbool.h"
+#include "stddef.h"
+#include "stdint.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+// cffi start
+
+// Type definitions
+typedef enum {
+    NIX_TYPE_THUNK,
+    NIX_TYPE_INT,
+    NIX_TYPE_FLOAT,
+    NIX_TYPE_BOOL,
+    NIX_TYPE_STRING,
+    NIX_TYPE_PATH,
+    NIX_TYPE_NULL,
+    NIX_TYPE_ATTRS,
+    NIX_TYPE_LIST,
+    NIX_TYPE_FUNCTION,
+    NIX_TYPE_EXTERNAL
+} ValueType;
+
+// forward declarations
+typedef void Value;
+typedef struct EvalState EvalState;
+// type defs
+/** @brief Stores an under-construction set of bindings
+ * @ingroup value_manip
+ *
+ * Do not reuse.
+ * @see nix_make_bindings_builder, nix_bindings_builder_free, nix_make_attrs
+ * @see nix_bindings_builder_insert
+ */
+typedef struct BindingsBuilder BindingsBuilder;
+
+/** @brief Stores an under-construction list
+ * @ingroup value_manip
+ *
+ * Do not reuse.
+ * @see nix_make_list_builder, nix_list_builder_free, nix_make_list
+ * @see nix_list_builder_insert
+ */
+typedef struct ListBuilder ListBuilder;
+
+/** @brief PrimOp function
+ * @ingroup primops
+ *
+ * Owned by the GC
+ * @see nix_alloc_primop, nix_init_primop
+ */
+typedef struct PrimOp PrimOp;
+/** @brief External Value
+ * @ingroup Externals
+ *
+ * Owned by the GC
+ */
+typedef struct ExternalValue ExternalValue;
+
+/** @defgroup primops
+ * @brief Create your own primops
+ * @{
+ */
+/** @brief Function pointer for primops
+ * When you want to return an error, call nix_set_err_msg(context, NIX_ERR_UNKNOWN, "your error message here").
+ *
+ * @param[in] user_data Arbitrary data that was initially supplied to nix_alloc_primop
+ * @param[out] context Stores error information.
+ * @param[in] state Evaluator state
+ * @param[in] args list of arguments. Note that these can be thunks and should be forced using nix_value_force before
+ * use.
+ * @param[out] ret return value
+ * @see nix_alloc_primop, nix_init_primop
+ */
+typedef void (*PrimOpFun)(void * user_data, nix_c_context * context, EvalState * state, Value ** args, Value * ret);
+
+/** @brief Allocate a PrimOp
+ *
+ * Owned by the garbage collector.
+ * Use nix_gc_decref() when you're done with the returned PrimOp.
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] fun callback
+ * @param[in] arity expected number of function arguments
+ * @param[in] name function name
+ * @param[in] args array of argument names, NULL-terminated
+ * @param[in] doc optional, documentation for this primop
+ * @param[in] user_data optional, arbitrary data, passed to the callback when it's called
+ * @return primop, or null in case of errors
+ * @see nix_init_primop
+ */
+PrimOp * nix_alloc_primop(
+    nix_c_context * context,
+    PrimOpFun fun,
+    int arity,
+    const char * name,
+    const char ** args,
+    const char * doc,
+    void * user_data);
+
+/** @brief add a primop to the `builtins` attribute set
+ *
+ * Only applies to States created after this call.
+ *
+ * Moves your PrimOp content into the global evaluator
+ * registry, meaning your input PrimOp pointer is no longer usable.
+ * You are free to remove your references to it,
+ * after which it will be garbage collected.
+ *
+ * @param[out] context Optional, stores error information
+ * @return primop, or null in case of errors
+ *
+ */
+nix_err nix_register_primop(nix_c_context * context, PrimOp * primOp);
+/** @} */
+
+// Function prototypes
+
+/** @brief Allocate a Nix value
+ *
+ * Owned by the GC. Use nix_gc_decref() when you're done with the pointer
+ * @param[out] context Optional, stores error information
+ * @param[in] state nix evaluator state
+ * @return value, or null in case of errors
+ *
+ */
+
+Value * nix_alloc_value(nix_c_context * context, EvalState * state);
+/** @addtogroup value_manip Manipulating values
+ * @brief Functions to inspect and change Nix language values, represented by Value.
+ * @{
+ */
+/** @name Getters
+ */
+/**@{*/
+/** @brief Get value type
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return type of nix value
+ */
+
+ValueType nix_get_type(nix_c_context * context, const Value * value);
+/** @brief Get type name of value as defined in the evaluator
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return type name, owned string
+ * @todo way to free the result
+ */
+
+const char * nix_get_typename(nix_c_context * context, const Value * value);
+
+/** @brief Get boolean value
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return true or false, error info via context
+ */
+bool nix_get_bool(nix_c_context * context, const Value * value);
+/** @brief Get string
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return string
+ * @return NULL in case of error.
+ */
+const char * nix_get_string(nix_c_context * context, const Value * value);
+
+/** @brief Get path as string
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return string
+ * @return NULL in case of error.
+ */
+const char * nix_get_path_string(nix_c_context * context, const Value * value);
+
+/** @brief Get the length of a list
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return length of list, error info via context
+ */
+unsigned int nix_get_list_size(nix_c_context * context, const Value * value);
+
+/** @brief Get the element count of an attrset
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return attrset element count, error info via context
+ */
+unsigned int nix_get_attrs_size(nix_c_context * context, const Value * value);
+
+/** @brief Get float value in 64 bits
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return float contents, error info via context
+ */
+double nix_get_float(nix_c_context * context, const Value * value);
+
+/** @brief Get int value
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return int contents, error info via context
+ */
+int64_t nix_get_int(nix_c_context * context, const Value * value);
+
+/** @brief Get external reference
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @return reference to external, NULL in case of error
+ */
+ExternalValue * nix_get_external(nix_c_context * context, Value *);
+
+/** @brief Get the ix'th element of a list
+ *
+ * Owned by the GC. Use nix_gc_decref when you're done with the pointer
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @param[in] state nix evaluator state
+ * @param[in] ix list element to get
+ * @return value, NULL in case of errors
+ */
+Value * nix_get_list_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int ix);
+
+/** @brief Get an attr by name
+ *
+ * Owned by the GC. Use nix_gc_decref when you're done with the pointer
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @param[in] state nix evaluator state
+ * @param[in] name attribute name
+ * @return value, NULL in case of errors
+ */
+Value * nix_get_attr_byname(nix_c_context * context, const Value * value, EvalState * state, const char * name);
+
+/** @brief Check if an attribute name exists on a value
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @param[in] state nix evaluator state
+ * @param[in] name attribute name
+ * @return value, error info via context
+ */
+bool nix_has_attr_byname(nix_c_context * context, const Value * value, EvalState * state, const char * name);
+
+/** @brief Get an attribute by index in the sorted bindings
+ *
+ * Also gives you the name.
+ *
+ * Owned by the GC. Use nix_gc_decref when you're done with the pointer
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @param[in] state nix evaluator state
+ * @param[in] i attribute index
+ * @param[out] name will store a pointer to the attribute name
+ * @return value, NULL in case of errors
+ */
+Value *
+nix_get_attr_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int i, const char ** name);
+
+/** @brief Get an attribute name by index in the sorted bindings
+ *
+ * Useful when you want the name but want to avoid evaluation.
+ *
+ * Owned by the nix EvalState
+ * @param[out] context Optional, stores error information
+ * @param[in] value Nix value to inspect
+ * @param[in] state nix evaluator state
+ * @param[in] i attribute index
+ * @return name, NULL in case of errors
+ */
+const char * nix_get_attr_name_byidx(nix_c_context * context, const Value * value, EvalState * state, unsigned int i);
+
+/**@}*/
+/** @name Initializers
+ *
+ * Values are typically "returned" by initializing already allocated memory that serves as the return value.
+ * For this reason, the construction of values is not tied their allocation.
+ * Nix is a language with immutable values. Respect this property by only initializing Values once; and only initialize
+ * Values that are meant to be initialized by you. Failing to adhere to these rules may lead to undefined behavior.
+ */
+/**@{*/
+/** @brief Set boolean value
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] b the boolean value
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_bool(nix_c_context * context, Value * value, bool b);
+
+/** @brief Set a string
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] str the string, copied
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_string(nix_c_context * context, Value * value, const char * str);
+
+/** @brief Set a path
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] str the path string, copied
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_path_string(nix_c_context * context, EvalState * s, Value * value, const char * str);
+
+/** @brief Set a float
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] d the float, 64-bits
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_float(nix_c_context * context, Value * value, double d);
+
+/** @brief Set an int
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] i the int
+ * @return error code, NIX_OK on success.
+ */
+
+nix_err nix_init_int(nix_c_context * context, Value * value, int64_t i);
+/** @brief Set null
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @return error code, NIX_OK on success.
+ */
+
+nix_err nix_init_null(nix_c_context * context, Value * value);
+/** @brief Set an external value
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] val the external value to set. Will be GC-referenced by the value.
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_external(nix_c_context * context, Value * value, ExternalValue * val);
+
+/** @brief Create a list from a list builder
+ * @param[out] context Optional, stores error information
+ * @param[in] list_builder list builder to use. Make sure to unref this afterwards.
+ * @param[out] value Nix value to modify
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_make_list(nix_c_context * context, EvalState * s, ListBuilder * list_builder, Value * value);
+
+/** @brief Create a list builder
+ * @param[out] context Optional, stores error information
+ * @param[in] state nix evaluator state
+ * @param[in] capacity how many bindings you'll add. Don't exceed.
+ * @return owned reference to a list builder. Make sure to unref when you're done.
+ */
+ListBuilder * nix_make_list_builder(nix_c_context * context, EvalState * state, size_t capacity);
+
+/** @brief Insert bindings into a builder
+ * @param[out] context Optional, stores error information
+ * @param[in] list_builder ListBuilder to insert into
+ * @param[in] value value to insert
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_list_builder_insert(nix_c_context * context, ListBuilder * list_builder, Value * value);
+
+/** @brief Free a list builder
+ *
+ * Does not fail.
+ * @param[in] builder the builder to free
+ */
+void nix_list_builder_free(ListBuilder * builder);
+
+/** @brief Create an attribute set from a bindings builder
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] b bindings builder to use. Make sure to unref this afterwards.
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_make_attrs(nix_c_context * context, Value * value, BindingsBuilder * b);
+
+/** @brief Set primop
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] op primop, will be gc-referenced by the value
+ * @see nix_alloc_primop
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_init_primop(nix_c_context * context, Value * value, PrimOp * op);
+/** @brief Copy from another value
+ * @param[out] context Optional, stores error information
+ * @param[out] value Nix value to modify
+ * @param[in] source value to copy from
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_copy_value(nix_c_context * context, Value * value, Value * source);
+/**@}*/
+
+/** @brief Create a bindings builder
+* @param[out] context Optional, stores error information
+* @param[in] state nix evaluator state
+* @param[in] capacity how many bindings you'll add. Don't exceed.
+* @return owned reference to a bindings builder. Make sure to unref when you're
+done.
+*/
+BindingsBuilder * nix_make_bindings_builder(nix_c_context * context, EvalState * state, size_t capacity);
+
+/** @brief Insert bindings into a builder
+ * @param[out] context Optional, stores error information
+ * @param[in] builder BindingsBuilder to insert into
+ * @param[in] name attribute name, copied into the symbol store
+ * @param[in] value value to give the binding
+ * @return error code, NIX_OK on success.
+ */
+nix_err
+nix_bindings_builder_insert(nix_c_context * context, BindingsBuilder * builder, const char * name, Value * value);
+
+/** @brief Free a bindings builder
+ *
+ * Does not fail.
+ * @param[in] builder the builder to free
+ */
+void nix_bindings_builder_free(BindingsBuilder * builder);
+/**@}*/
+
+// cffi end
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
+#endif // NIX_API_VALUE_H
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@ -36,7 +36,7 @@ enum RepairFlag : bool;
 /**
 * Function that implements a primop.
 */
-typedef void (* PrimOpFun) (EvalState & state, const PosIdx pos, Value * * args, Value & v);
+typedef std::function<void (EvalState &, const PosIdx, Value **, Value &)> PrimOpFun;

 /**
 * Info about a primitive operation, and its implementation
--- a/src/libexpr/meson.build
+++ b/src/libexpr/meson.build
@ -0,0 +1,91 @@
+bison = find_program('bison')
+flex = find_program('flex')
+
+parser_tab = custom_target(
+  input : 'parser.y',
+  output : [
+    'parser-tab.cc',
+    'parser-tab.hh',
+  ],
+  command : [
+    'bison',
+    '-v',
+    '-o',
+    '@OUTPUT0@',
+    '@INPUT@',
+    '-d',
+  ],
+)
+
+lexer_tab = custom_target(
+  input : [
+    'lexer.l',
+    parser_tab,
+  ],
+  output : [
+    'lexer-tab.cc',
+    'lexer-tab.hh',
+  ],
+  command : [
+    'flex',
+    '--outfile',
+    '@OUTPUT0@',
+    '--header-file=' + '@OUTPUT1@',
+    '@INPUT0@',
+  ],
+)
+
+libexpr_sources = files(
+  'attr-path.cc',
+  'attr-set.cc',
+  'eval-cache.cc',
+  'eval-error.cc',
+  'eval-settings.cc',
+  'eval.cc',
+  'function-trace.cc',
+  'get-drvs.cc',
+  'json-to-value.cc',
+  'nixexpr.cc',
+  'paths.cc',
+  'primops.cc',
+  'print-ambiguous.cc',
+  'print.cc',
+  'search-path.cc',
+  'value-to-json.cc',
+  'value-to-xml.cc',
+  'flake/config.cc',
+  'flake/flake.cc',
+  'flake/flakeref.cc',
+  'flake/lockfile.cc',
+  'primops/context.cc',
+  'primops/fetchClosure.cc',
+  'primops/fetchMercurial.cc',
+  'primops/fetchTree.cc',
+  'primops/fromTOML.cc',
+  'value/context.cc',
+)
+
+all_sources += {
+  'libexpr': libexpr_sources
+}
+
+libexpr = library(
+  'nixexpr',
+  libexpr_sources,
+  parser_tab,
+  lexer_tab,
+  dependencies : [
+    liblixutil,
+    liblixstore,
+    liblixfetchers,
+    boehm,
+    boost,
+  ],
+)
+
+liblixexpr = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libexpr,
+)
+
+subdir('c')
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@ -3279,8 +3279,11 @@ static void prim_sort(EvalState & state, const PosIdx pos, Value * * args, Value
           callFunction. */
        /* TODO: (layus) this is absurd. An optimisation like this
           should be outside the lambda creation */
-        if (args[0]->isPrimOp() && args[0]->primOp->fun == prim_lessThan)
-            return CompareValues(state, noPos, "while evaluating the ordering function passed to builtins.sort")(a, b);
+        if (args[0]->isPrimOp()) {
+            auto target = args[0]->primOp->fun.target<decltype(&prim_lessThan)>();
+            if (target && *target == prim_lessThan)
+                return CompareValues(state, noPos, "while evaluating the ordering function passed to builtins.sort")(a, b);
+        }

        Value * vs[] = {a, b};
        Value vBool;
--- a/src/libexpr/search-path.cc
+++ b/src/libexpr/search-path.cc
@ -45,7 +45,7 @@ SearchPath::Elem SearchPath::Elem::parse(std::string_view rawElem)
 }


-SearchPath parseSearchPath(const Strings & rawElems)
+SearchPath SearchPath::parse(const Strings & rawElems)
 {
    SearchPath res;
    for (auto & rawElem : rawElems)
--- a/src/libexpr/value.hh
+++ b/src/libexpr/value.hh
@ -384,7 +384,7 @@ public:
        return internalType == tList1 || internalType == tList2 ? smallList : bigList.elems;
    }

-    const Value * const * listElems() const
+    Value * const * listElems() const
    {
        return internalType == tList1 || internalType == tList2 ? smallList : bigList.elems;
    }
--- a/src/libfetchers/meson.build
+++ b/src/libfetchers/meson.build
@ -0,0 +1,28 @@
+libfetchers_sources = files(
+  'attrs.cc',
+  'cache.cc',
+  'fetch-settings.cc',
+  'fetch-to-store.cc',
+  'fetchers.cc',
+  'git.cc',
+  'github.cc',
+  'indirect.cc',
+  'mercurial.cc',
+  'path.cc',
+  'registry.cc',
+  'tarball.cc',
+)
+
+libfetchers = library(
+  'nixfetchers',
+  libfetchers_sources,
+  dependencies : [
+    liblixstore,
+    liblixutil,
+  ],
+)
+
+liblixfetchers = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libfetchers,
+)
--- a/src/libmain/meson.build
+++ b/src/libmain/meson.build
@ -0,0 +1,21 @@
+libmain_sources = files(
+  'common-args.cc',
+  'loggers.cc',
+  'progress-bar.cc',
+  'shared.cc',
+  'stack.cc',
+)
+
+libmain = library(
+  'nixmain',
+  libmain_sources,
+  dependencies : [
+    liblixutil,
+    liblixstore,
+  ],
+)
+
+liblixmain = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libmain,
+)
--- a/src/libstore/c/meson.build
+++ b/src/libstore/c/meson.build
@ -0,0 +1,26 @@
+pkg = import('pkgconfig')
+
+libstorec_sources = files(
+  'nix_api_store.cc',
+)
+
+all_sources += {
+  'libstorec': libstorec_sources,
+}
+
+libstorec = library(
+  'nix-store-c',
+  libstorec_sources,
+  dependencies : [
+    liblixutil, # Internal.
+    liblixstore, # Internal.
+    liblixutilc, # Internal.
+  ],
+)
+
+pkg.generate(libstorec, requires : [ 'nix-util-c' ])
+
+liblixstorec = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libstorec,
+)
--- a/src/libstore/c/nix_api_store.cc
+++ b/src/libstore/c/nix_api_store.cc
@ -0,0 +1,136 @@
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+
+#include "path.hh"
+#include "store-api.hh"
+#include "build-result.hh"
+
+#include "globals.hh"
+
+nix_err nix_libstore_init(nix_c_context * context)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::initLibStore();
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_init_plugins(nix_c_context * context)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::initPlugins();
+    }
+    NIXC_CATCH_ERRS
+}
+
+Store * nix_store_open(nix_c_context * context, const char * uri, const char *** params)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        std::string uri_str = uri ? uri : "";
+
+        if (uri_str.empty())
+            return new Store{nix::openStore()};
+
+        if (!params)
+            return new Store{nix::openStore(uri_str)};
+
+        nix::Store::Params params_map;
+        for (size_t i = 0; params[i] != nullptr; i++) {
+            params_map[params[i][0]] = params[i][1];
+        }
+        return new Store{nix::openStore(uri_str, params_map)};
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+void nix_store_free(Store * store)
+{
+    delete store;
+}
+
+nix_err nix_store_get_uri(nix_c_context * context, Store * store, char * dest, unsigned int n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto res = store->ptr->getUri();
+        return nix_export_std_string(context, res, dest, n);
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_store_get_version(nix_c_context * context, Store * store, char * dest, unsigned int n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        auto res = store->ptr->getVersion();
+        if (!res)
+            res = "";
+        return nix_export_std_string(context, *res, dest, n);
+    }
+    NIXC_CATCH_ERRS
+}
+
+bool nix_store_is_valid_path(nix_c_context * context, Store * store, StorePath * path)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        return store->ptr->isValidPath(path->path);
+    }
+    NIXC_CATCH_ERRS_RES(false);
+}
+
+StorePath * nix_store_parse_path(nix_c_context * context, Store * store, const char * path)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::StorePath s = store->ptr->parseStorePath(path);
+        return new StorePath{std::move(s)};
+    }
+    NIXC_CATCH_ERRS_NULL
+}
+
+nix_err nix_store_realise(
+    nix_c_context * context,
+    Store * store,
+    StorePath * path,
+    void * userdata,
+    void (*callback)(void * userdata, const char *, const char *))
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+
+        const std::vector<nix::DerivedPath> paths{nix::DerivedPath::Built{
+            .drvPath = nix::makeConstantStorePathRef(path->path), .outputs = nix::OutputsSpec::All{}}};
+
+        const auto nixStore = store->ptr;
+        auto results = nixStore->buildPathsWithResults(paths, nix::bmNormal, nixStore);
+
+        if (callback) {
+            for (const auto & result : results) {
+                for (const auto & [outputName, realisation] : result.builtOutputs) {
+                    auto op = store->ptr->printStorePath(realisation.outPath);
+                    callback(userdata, outputName.c_str(), op.c_str());
+                }
+            }
+        }
+    }
+    NIXC_CATCH_ERRS
+}
+
+void nix_store_path_free(StorePath * sp)
+{
+    delete sp;
+}
--- a/src/libstore/c/nix_api_store.h
+++ b/src/libstore/c/nix_api_store.h
@ -0,0 +1,146 @@
+#ifndef NIX_API_STORE_H
+#define NIX_API_STORE_H
+/**
+ * @defgroup libstore libstore
+ * @brief C bindings for nix libstore
+ *
+ * libstore is used for talking to a Nix store
+ * @{
+ */
+/** @file
+ * @brief Main entry for the libstore C bindings
+ */
+
+#include "nix_api_util.h"
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+// cffi start
+
+/** @brief Reference to a Nix store */
+typedef struct Store Store;
+/** @brief Nix store path */
+typedef struct StorePath StorePath;
+
+/**
+ * @brief Initializes the Nix store library
+ *
+ * This function should be called before creating a Store
+ * This function can be called multiple times.
+ *
+ * @param[out] context Optional, stores error information
+ * @return NIX_OK if the initialization was successful, an error code otherwise.
+ */
+nix_err nix_libstore_init(nix_c_context * context);
+
+/**
+ * @brief Loads the plugins specified in Nix's plugin-files setting.
+ *
+ * Call this once, after calling your desired init functions and setting
+ * relevant settings.
+ *
+ * @param[out] context Optional, stores error information
+ * @return NIX_OK if the initialization was successful, an error code otherwise.
+ */
+nix_err nix_init_plugins(nix_c_context * context);
+
+/**
+ * @brief Open a nix store
+ * Store instances may share state and resources behind the scenes.
+ * @param[out] context Optional, stores error information
+ * @param[in] uri URI of the nix store, copied
+ * @param[in] params optional, array of key-value pairs, {{"endpoint",
+ * "https://s3.local"}}
+ * @return a Store pointer, NULL in case of errors
+ * @see nix_store_free
+ */
+Store * nix_store_open(nix_c_context *, const char * uri, const char *** params);
+
+/**
+ * @brief Deallocate a nix store and free any resources if not also held by other Store instances.
+ *
+ * Does not fail.
+ *
+ * @param[in] store the store to free
+ */
+void nix_store_free(Store * store);
+
+/**
+ * @brief get the URI of a nix store
+ * @param[out] context Optional, stores error information
+ * @param[in] store nix store reference
+ * @param[out] dest The allocated area to write the string to.
+ * @param[in] n Maximum size of the returned string.
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_store_get_uri(nix_c_context * context, Store * store, char * dest, unsigned int n);
+
+// returns: owned StorePath*
+/**
+ * @brief Parse a Nix store path into a StorePath
+ *
+ * @note Don't forget to free this path using nix_store_path_free()!
+ * @param[out] context Optional, stores error information
+ * @param[in] store nix store reference
+ * @param[in] path Path string to parse, copied
+ * @return owned store path, NULL on error
+ */
+StorePath * nix_store_parse_path(nix_c_context * context, Store * store, const char * path);
+
+/** @brief Deallocate a StorePath
+ *
+ * Does not fail.
+ * @param[in] p the path to free
+ */
+void nix_store_path_free(StorePath * p);
+
+/**
+ * @brief Check if a StorePath is valid (i.e. that corresponding store object and its closure of references exists in
+ * the store)
+ * @param[out] context Optional, stores error information
+ * @param[in] store Nix Store reference
+ * @param[in] path Path to check
+ * @return true or false, error info in context
+ */
+bool nix_store_is_valid_path(nix_c_context * context, Store * store, StorePath * path);
+// nix_err nix_store_ensure(Store*, const char*);
+// nix_err nix_store_build_paths(Store*);
+/**
+ * @brief Realise a Nix store path
+ *
+ * Blocking, calls callback once for each realised output
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] store Nix Store reference
+ * @param[in] path Path to build
+ * @param[in] userdata data to pass to every callback invocation
+ * @param[in] callback called for every realised output
+ */
+nix_err nix_store_realise(
+    nix_c_context * context,
+    Store * store,
+    StorePath * path,
+    void * userdata,
+    void (*callback)(void * userdata, const char * outname, const char * out));
+
+/**
+ * @brief get the version of a nix store.
+ * If the store doesn't have a version (like the dummy store), returns an empty string.
+ * @param[out] context Optional, stores error information
+ * @param[in] store nix store reference
+ * @param[out] dest The allocated area to write the string to.
+ * @param[in] n Maximum size of the returned string.
+ * @return error code, NIX_OK on success.
+ */
+nix_err nix_store_get_version(nix_c_context *, Store * store, char * dest, unsigned int n);
+
+// cffi end
+#ifdef __cplusplus
+}
+#endif
+/**
+ * @}
+ */
+#endif // NIX_API_STORE_H
--- a/src/libstore/c/nix_api_store_internal.h
+++ b/src/libstore/c/nix_api_store_internal.h
@ -0,0 +1,15 @@
+#ifndef NIX_API_STORE_INTERNAL_H
+#define NIX_API_STORE_INTERNAL_H
+#include "store-api.hh"
+
+struct Store
+{
+    nix::ref<nix::Store> ptr;
+};
+
+struct StorePath
+{
+    nix::StorePath path;
+};
+
+#endif
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@ -0,0 +1,124 @@
+schema_sql_gen = gen_header.process('schema.sql')
+ca_specific_schema_gen = gen_header.process('ca-specific-schema.sql')
+
+libstore_sources = files(
+  'binary-cache-store.cc',
+  'build-result.cc',
+  'common-protocol.cc',
+  'content-address.cc',
+  'crypto.cc',
+  'daemon.cc',
+  'derivations.cc',
+  'derived-path-map.cc',
+  'derived-path.cc',
+  'downstream-placeholder.cc',
+  'dummy-store.cc',
+  'export-import.cc',
+  'filetransfer.cc',
+  'gc.cc',
+  'globals.cc',
+  'http-binary-cache-store.cc',
+  'legacy-ssh-store.cc',
+  'local-binary-cache-store.cc',
+  'local-fs-store.cc',
+  'local-store.cc',
+  'lock.cc',
+  'log-store.cc',
+  'machines.cc',
+  'make-content-addressed.cc',
+  'misc.cc',
+  'names.cc',
+  'nar-accessor.cc',
+  'nar-info-disk-cache.cc',
+  'nar-info.cc',
+  'optimise-store.cc',
+  'outputs-spec.cc',
+  'parsed-derivations.cc',
+  'path-info.cc',
+  'path-references.cc',
+  'path-with-outputs.cc',
+  'path.cc',
+  'pathlocks.cc',
+  'profiles.cc',
+  'realisation.cc',
+  'remote-fs-accessor.cc',
+  'remote-store.cc',
+  's3-binary-cache-store.cc',
+  'serve-protocol.cc',
+  'sqlite.cc',
+  'ssh-store.cc',
+  'ssh.cc',
+  'store-api.cc',
+  'uds-remote-store.cc',
+  'worker-protocol.cc',
+  'build/derivation-goal.cc',
+  'build/drv-output-substitution-goal.cc',
+  'build/entry-points.cc',
+  'build/goal.cc',
+  'build/hook-instance.cc',
+  'build/local-derivation-goal.cc',
+  'build/personality.cc',
+  'build/substitution-goal.cc',
+  'build/worker.cc',
+  'builtins/buildenv.cc',
+  'builtins/fetchurl.cc',
+  'builtins/unpack-channel.cc',
+)
+
+all_sources += {
+  'libstore': libstore_sources,
+}
+
+prefix = get_option('prefix')
+
+cpp_str_defines = {
+  'LSOF': lsof.full_path(),
+  'NIX_PREFIX':    get_option('prefix'),
+  'NIX_STORE_DIR': get_option('store-dir'),
+  'NIX_DATA_DIR':  get_option('prefix') / 'share', # FIXME: make separately-configurable
+  #'NIX_STATE_DIR': get_option('prefix') / 'nix', # FIXME: same
+  'NIX_LOG_DIR':   get_option('prefix') / 'log' / 'nix', # FIXME: same
+  'NIX_CONF_DIR':  get_option('prefix') / 'etc', # FIXME: same
+  'NIX_BIN_DIR':   get_option('prefix') / 'bin', # FIXME: same
+  'NIX_MAN_DIR':   get_option('prefix') / 'share' / 'man', # FIXME: same
+}
+
+cpp_str_defines += {
+  'NIX_STATE_DIR': '/nix/var/nix',
+}
+
+cpp_args = []
+
+foreach name, value : cpp_str_defines
+  cpp_args += [
+    '-D' + name + '=' + '"' + value + '"'
+  ]
+endforeach
+
+libstore = library(
+  'nixstore',
+  schema_sql_gen,
+  ca_specific_schema_gen,
+  libstore_sources,
+  dependencies : [
+    libarchive,
+    liblixutil, # Internal.
+    seccomp,
+    sqlite,
+    sodium,
+    curl,
+    openssl,
+    aws_sdk,
+    aws_s3,
+    aws_sdk_transfer,
+  ],
+  cpp_args : cpp_args,
+)
+
+# Used by libfetchers.
+liblixstore = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libstore,
+)
+
+subdir('c')
--- a/src/libutil/c/meson.build
+++ b/src/libutil/c/meson.build
@ -0,0 +1,25 @@
+pkg = import('pkgconfig')
+
+libutilc_sources = files(
+  'nix_api_util.cc',
+)
+
+all_sources += {
+  'libutilc': libutilc_sources,
+}
+
+libutilc = library(
+  'nix-util-c',
+  libutilc_sources,
+  dependencies : [
+    liblixutil,
+  ],
+  implicit_include_directories : true,
+)
+
+pkg.generate(libutilc)
+
+liblixutilc = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libutilc
+)
--- a/src/libutil/c/nix_api_util.cc
+++ b/src/libutil/c/nix_api_util.cc
@ -0,0 +1,151 @@
+#include "nix_api_util.h"
+#include "config.hh"
+#include "error.hh"
+#include "nix_api_util_internal.h"
+#include "util.hh"
+
+#include <cxxabi.h>
+#include <typeinfo>
+
+nix_c_context * nix_c_context_create()
+{
+    return new nix_c_context();
+}
+
+void nix_c_context_free(nix_c_context * context)
+{
+    delete context;
+}
+
+nix_err nix_context_error(nix_c_context * context)
+{
+    if (context == nullptr) {
+        throw;
+    }
+    try {
+        throw;
+    } catch (nix::Error & e) {
+        /* Storing this exception is annoying, take what we need here */
+        context->last_err = e.what();
+        context->info = e.info();
+        int status;
+        const char * demangled = abi::__cxa_demangle(typeid(e).name(), 0, 0, &status);
+        if (demangled) {
+            context->name = demangled;
+            // todo: free(demangled);
+        } else {
+            context->name = typeid(e).name();
+        }
+        context->last_err_code = NIX_ERR_NIX_ERROR;
+        return context->last_err_code;
+    } catch (const std::exception & e) {
+        context->last_err = e.what();
+        context->last_err_code = NIX_ERR_UNKNOWN;
+        return context->last_err_code;
+    }
+    // unreachable
+}
+
+nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg)
+{
+    if (context == nullptr) {
+        // todo last_err_code
+        throw nix::Error("Nix C api error: %s", msg);
+    }
+    context->last_err_code = err;
+    context->last_err = msg;
+    return err;
+}
+
+const char * nix_version_get()
+{
+    return PACKAGE_VERSION;
+}
+
+// Implementations
+nix_err nix_setting_get(nix_c_context * context, const char * key, char * value, int n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        std::map<std::string, nix::AbstractConfig::SettingInfo> settings;
+        nix::globalConfig.getSettings(settings);
+        if (settings.contains(key))
+            return nix_export_std_string(context, settings[key].value, value, n);
+        else {
+            return nix_set_err_msg(context, NIX_ERR_KEY, "Setting not found");
+        }
+    }
+    NIXC_CATCH_ERRS
+}
+
+nix_err nix_setting_set(nix_c_context * context, const char * key, const char * value)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (nix::globalConfig.set(key, value))
+        return NIX_OK;
+    else {
+        return nix_set_err_msg(context, NIX_ERR_KEY, "Setting not found");
+    }
+}
+
+nix_err nix_libutil_init(nix_c_context * context)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    try {
+        nix::initLibUtil();
+        return NIX_OK;
+    }
+    NIXC_CATCH_ERRS
+}
+
+const char * nix_err_msg(nix_c_context * context, const nix_c_context * read_context, unsigned int * n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (read_context->last_err) {
+        if (n)
+            *n = read_context->last_err->size();
+        return read_context->last_err->c_str();
+    }
+    nix_set_err_msg(context, NIX_ERR_UNKNOWN, "No error message");
+    return nullptr;
+}
+
+nix_err nix_err_name(nix_c_context * context, const nix_c_context * read_context, char * value, int n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (read_context->last_err_code != NIX_ERR_NIX_ERROR) {
+        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Last error was not a nix error");
+    }
+    return nix_export_std_string(context, read_context->name, value, n);
+}
+
+nix_err nix_err_info_msg(nix_c_context * context, const nix_c_context * read_context, char * value, int n)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (read_context->last_err_code != NIX_ERR_NIX_ERROR) {
+        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Last error was not a nix error");
+    }
+    return nix_export_std_string(context, read_context->info->msg.str(), value, n);
+}
+
+nix_err nix_err_code(const nix_c_context * read_context)
+{
+    return read_context->last_err_code;
+}
+
+// internal
+nix_err nix_export_std_string(nix_c_context * context, const std::string_view str, char * dest, unsigned int n)
+{
+    size_t i = str.copy(dest, n - 1);
+    dest[i] = 0;
+    if (i == n - 1) {
+        return nix_set_err_msg(context, NIX_ERR_OVERFLOW, "Provided buffer too short");
+    } else
+        return NIX_OK;
+}
--- a/src/libutil/c/nix_api_util.h
+++ b/src/libutil/c/nix_api_util.h
@ -0,0 +1,290 @@
+#ifndef NIX_API_UTIL_H
+#define NIX_API_UTIL_H
+/**
+ * @defgroup libutil libutil
+ * @brief C bindings for nix libutil
+ *
+ * libutil is used for functionality shared between
+ * different Nix modules.
+ * @{
+ */
+/** @file
+ * @brief Main entry for the libutil C bindings
+ *
+ * Also contains error handling utilities
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+// cffi start
+
+/** @defgroup errors Handling errors
+ * @brief Dealing with errors from the Nix side
+ *
+ * To handle errors that can be returned from the Nix API,
+ * a nix_c_context can be passed to any function that potentially returns an
+ * error.
+ *
+ * Error information will be stored in this context, and can be retrieved
+ * using nix_err_code and nix_err_msg.
+ *
+ * Passing NULL instead will cause the API to throw C++ errors.
+ *
+ * Example:
+ * @code{.c}
+ * int main() {
+ *     nix_c_context* ctx = nix_c_context_create();
+ *     nix_libutil_init(ctx);
+ *     if (nix_err_code(ctx) != NIX_OK) {
+ *         printf("error: %s\n", nix_err_msg(NULL, ctx, NULL));
+ *         return 1;
+ *     }
+ *     return 0;
+ * }
+ * @endcode
+ *  @{
+ */
+// Error codes
+/**
+ * @brief Type for error codes in the NIX system
+ *
+ * This type can have one of several predefined constants:
+ * - NIX_OK: No error occurred (0)
+ * - NIX_ERR_UNKNOWN: An unknown error occurred (-1)
+ * - NIX_ERR_OVERFLOW: An overflow error occurred (-2)
+ * - NIX_ERR_KEY: A key error occurred (-3)
+ * - NIX_ERR_NIX_ERROR: A generic Nix error occurred (-4)
+ */
+typedef int nix_err;
+
+/**
+ * @brief No error occurred.
+ *
+ * This error code is returned when no error has occurred during the function
+ * execution.
+ */
+#define NIX_OK 0
+
+/**
+ * @brief An unknown error occurred.
+ *
+ * This error code is returned when an unknown error occurred during the
+ * function execution.
+ */
+#define NIX_ERR_UNKNOWN -1
+
+/**
+ * @brief An overflow error occurred.
+ *
+ * This error code is returned when an overflow error occurred during the
+ * function execution.
+ */
+#define NIX_ERR_OVERFLOW -2
+
+/**
+ * @brief A key error occurred.
+ *
+ * This error code is returned when a key error occurred during the function
+ * execution.
+ */
+#define NIX_ERR_KEY -3
+
+/**
+ * @brief A generic Nix error occurred.
+ *
+ * This error code is returned when a generic Nix error occurred during the
+ * function execution.
+ */
+#define NIX_ERR_NIX_ERROR -4
+
+/**
+ * @brief This object stores error state.
+ * @struct nix_c_context
+ *
+ * Passed as a first parameter to functions that can fail, to store error
+ * information.
+ *
+ * Optional wherever it can be used, passing NULL instead will throw a C++
+ * exception.
+ *
+ * The struct is laid out so that it can also be cast to nix_err* to inspect
+ * directly:
+ * @code{.c}
+ * assert(*(nix_err*)ctx == NIX_OK);
+ * @endcode
+ * @note These can be reused between different function calls,
+ *  but make sure not to use them for multiple calls simultaneously (which can
+ * happen in callbacks).
+ */
+typedef struct nix_c_context nix_c_context;
+
+// Function prototypes
+
+/**
+ * @brief Allocate a new nix_c_context.
+ * @throws std::bad_alloc
+ * @return allocated nix_c_context, owned by the caller. Free using
+ * `nix_c_context_free`.
+ */
+nix_c_context * nix_c_context_create();
+/**
+ * @brief Free a nix_c_context. Does not fail.
+ * @param[out] context The context to free, mandatory.
+ */
+void nix_c_context_free(nix_c_context * context);
+/**
+ *  @}
+ */
+
+/**
+ * @brief Initializes nix_libutil and its dependencies.
+ *
+ * This function can be called multiple times, but should be called at least
+ * once prior to any other nix function.
+ *
+ * @param[out] context Optional, stores error information
+ * @return NIX_OK if the initialization is successful, or an error code
+ * otherwise.
+ */
+nix_err nix_libutil_init(nix_c_context * context);
+
+/** @defgroup settings
+ *  @{
+ */
+/**
+ * @brief Retrieves a setting from the nix global configuration.
+ *
+ * This function requires nix_libutil_init() to be called at least once prior to
+ * its use.
+ *
+ * @param[out] context optional, Stores error information
+ * @param[in] key The key of the setting to retrieve.
+ * @param[out] value A pointer to a buffer where the value of the setting will
+ * be stored.
+ * @param[in] n The size of the buffer pointed to by value.
+ * @return NIX_ERR_KEY if the setting is unknown, NIX_ERR_OVERFLOW if the
+ * provided buffer is too short, or NIX_OK if the setting was retrieved
+ * successfully.
+ */
+nix_err nix_setting_get(nix_c_context * context, const char * key, char * value, int n);
+
+/**
+ * @brief Sets a setting in the nix global configuration.
+ *
+ * Use "extra-<setting name>" to append to the setting's value.
+ *
+ * Settings only apply for new State%s. Call nix_plugins_init() when you are
+ * done with the settings to load any plugins.
+ *
+ * @param[out] context optional, Stores error information
+ * @param[in] key The key of the setting to set.
+ * @param[in] value The value to set for the setting.
+ * @return NIX_ERR_KEY if the setting is unknown, or NIX_OK if the setting was
+ * set successfully.
+ */
+nix_err nix_setting_set(nix_c_context * context, const char * key, const char * value);
+
+/**
+ *  @}
+ */
+// todo: nix_plugins_init()
+
+/**
+ * @brief Retrieves the nix library version.
+ *
+ * Does not fail.
+ * @return A static string representing the version of the nix library.
+ */
+const char * nix_version_get();
+
+/** @addtogroup errors
+ *  @{
+ */
+/**
+ * @brief Retrieves the most recent error message from a context.
+ *
+ * @pre This function should only be called after a previous nix function has
+ * returned an error.
+ *
+ * @param[out] context optional, the context to store errors in if this function
+ * fails
+ * @param[in] ctx the context to retrieve the error message from
+ * @param[out] n optional: a pointer to an unsigned int that is set to the
+ * length of the error.
+ * @return nullptr if no error message was ever set,
+ *         a borrowed pointer to the error message otherwise.
+ */
+const char * nix_err_msg(nix_c_context * context, const nix_c_context * ctx, unsigned int * n);
+
+/**
+ * @brief Retrieves the error message from errorInfo in a context.
+ *
+ * Used to inspect nix Error messages.
+ *
+ * @pre This function should only be called after a previous nix function has
+ * returned a NIX_ERR_NIX_ERROR
+ *
+ * @param[out] context optional, the context to store errors in if this function
+ * fails
+ * @param[in] read_context the context to retrieve the error message from
+ * @param[out] value The allocated area to write the error string to.
+ * @param[in] n Maximum size of the returned string.
+ * @return NIX_OK if there were no errors, an error code otherwise.
+ */
+nix_err nix_err_info_msg(nix_c_context * context, const nix_c_context * read_context, char * value, int n);
+
+/**
+ * @brief Retrieves the error name from a context.
+ *
+ * Used to inspect nix Error messages.
+ *
+ * @pre This function should only be called after a previous nix function has
+ * returned a NIX_ERR_NIX_ERROR
+ *
+ * @param context optional, the context to store errors in if this function
+ * fails
+ * @param[in] read_context the context to retrieve the error message from
+ * @param[out] value The allocated area to write the error string to.
+ * @param[in] n Maximum size of the returned string.
+ * @return NIX_OK if there were no errors, an error code otherwise.
+ */
+nix_err nix_err_name(nix_c_context * context, const nix_c_context * read_context, char * value, int n);
+
+/**
+ * @brief Retrieves the most recent error code from a nix_c_context
+ *
+ * Equivalent to reading the first field of the context.
+ *
+ * Does not fail
+ *
+ * @param[in] read_context the context to retrieve the error message from
+ * @return most recent error code stored in the context.
+ */
+nix_err nix_err_code(const nix_c_context * read_context);
+
+/**
+ * @brief Set an error message on a nix context.
+ *
+ * This should be used when you want to throw an error from a PrimOp callback.
+ *
+ * All other use is internal to the API.
+ *
+ * @param context context to write the error message to, or NULL
+ * @param err The error code to set and return
+ * @param msg The error message to set.
+ * @returns the error code set
+ */
+nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg);
+
+/**
+ *  @}
+ */
+
+// cffi end
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */
+#endif // NIX_API_UTIL_H
--- a/src/libutil/c/nix_api_util_internal.h
+++ b/src/libutil/c/nix_api_util_internal.h
@ -0,0 +1,49 @@
+#ifndef NIX_API_UTIL_INTERNAL_H
+#define NIX_API_UTIL_INTERNAL_H
+
+#include <string>
+#include <optional>
+
+#include "error.hh"
+#include "nix_api_util.h"
+
+struct nix_c_context
+{
+    nix_err last_err_code = NIX_OK;
+    std::optional<std::string> last_err = {};
+    std::optional<nix::ErrorInfo> info = {};
+    std::string name = "";
+};
+
+nix_err nix_context_error(nix_c_context * context);
+
+/**
+ * Internal use only.
+ *
+ * Export a std::string across the C api boundary
+ * @param context optional, the context to store errors in if this function
+ * fails
+ * @param str The string to export
+ * @param value The allocated area to write the string to.
+ * @param n Maximum size of the returned string.
+ * @return NIX_OK if there were no errors, NIX_ERR_OVERFLOW if the string length
+ * exceeds `n`.
+ */
+nix_err nix_export_std_string(nix_c_context * context, const std::string_view str, char * dest, unsigned int n);
+
+#define NIXC_CATCH_ERRS \
+    catch (...) \
+    { \
+        return nix_context_error(context); \
+    } \
+    return NIX_OK;
+
+#define NIXC_CATCH_ERRS_RES(def) \
+    catch (...) \
+    { \
+        nix_context_error(context); \
+        return def; \
+    }
+#define NIXC_CATCH_ERRS_NULL NIXC_CATCH_ERRS_RES(nullptr)
+
+#endif // NIX_API_UTIL_INTERNAL_H
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@ -0,0 +1,59 @@
+libutil_sources = files(
+  'archive.cc',
+  'args.cc',
+  'canon-path.cc',
+  'cgroup.cc',
+  'compression.cc',
+  'compute-levels.cc',
+  'config.cc',
+  'english.cc',
+  'error.cc',
+  'experimental-features.cc',
+  'filesystem.cc',
+  'git.cc',
+  'hash.cc',
+  'hilite.cc',
+  'json-utils.cc',
+  'logging.cc',
+  'namespaces.cc',
+  'position.cc',
+  'references.cc',
+  'serialise.cc',
+  'source-path.cc',
+  'suggestions.cc',
+  'tarfile.cc',
+  'thread-pool.cc',
+  'url.cc',
+  'util.cc',
+  'xml-writer.cc',
+)
+
+all_sources += {
+  'libutil': libutil_sources,
+}
+
+libutil = library(
+  'nixutil',
+  libutil_sources,
+  dependencies : [
+    aws_sdk,
+    aws_s3,
+    boehm,
+    boost,
+    cpuid,
+    seccomp,
+    libarchive,
+    brotli,
+    openssl,
+  ],
+  implicit_include_directories : true,
+)
+
+# Used by libstore and libfetchers.
+liblixutil = declare_dependency(
+  include_directories : include_directories('.'),
+  link_with : libutil
+)
+
+subdir('c')
+
--- a/src/meson.build
+++ b/src/meson.build
@ -0,0 +1,65 @@
+# Subcomponents: these link into artifacts themselves, and have interdependencies.
+
+subdir('libutil')
+# Load-bearing order. libstore depends on libutil.
+subdir('libstore')
+# libfetchers depends on libstore
+subdir('libfetchers')
+# libexpr depends on all of the above
+subdir('libexpr')
+# libmain depends on libutil and libstore
+subdir('libmain')
+# libcmd depends on everything
+subdir('libcmd')
+
+
+# The rest of the subdirectories aren't separate components,
+# just source files in another directory, so we process them here.
+
+build_remote_sources = files(
+  'build-remote/build-remote.cc',
+)
+nix_build_sources = files(
+  'nix-build/nix-build.cc',
+)
+nix_channel_sources = files(
+  'nix-channel/nix-channel.cc',
+)
+unpack_channel_gen = gen_header.process('nix-channel/unpack-channel.nix')
+nix_collect_garbage_sources = files(
+  'nix-collect-garbage/nix-collect-garbage.cc',
+)
+nix_copy_closure_sources = files(
+  'nix-copy-closure/nix-copy-closure.cc',
+)
+nix_env_buildenv_gen = gen_header.process('nix-env/buildenv.nix')
+nix_env_sources = files(
+  'nix-env/nix-env.cc',
+  'nix-env/user-env.cc',
+)
+nix_instantiate_sources = files(
+  'nix-instantiate/nix-instantiate.cc',
+)
+nix_store_sources = files(
+  'nix-store/dotgraph.cc',
+  'nix-store/graphml.cc',
+  'nix-store/nix-store.cc',
+)
+
+# Hurray for Meson list flattening!
+nix2_commands_sources = [
+  build_remote_sources,
+  nix_build_sources,
+  nix_channel_sources,
+  unpack_channel_gen,
+  nix_collect_garbage_sources,
+  nix_copy_closure_sources,
+  nix_env_buildenv_gen,
+  nix_env_sources,
+  nix_instantiate_sources,
+  nix_store_sources,
+]
+
+# Finally, the nix command itself, which all of the other commands are implmented in terms of
+# as a multicall binary.
+subdir('nix')
--- a/src/nix-env/meson.build
+++ b/src/nix-env/meson.build
@ -0,0 +1,4 @@
+nix_env_sources = files(
+  'nix-env.cc',
+  'user-env.cc'
+)
--- a/src/nix/meson.build
+++ b/src/nix/meson.build
@ -0,0 +1,68 @@
+generate_manpage_gen = gen_header.process(meson.project_source_root() / 'doc/manual/generate-manpage.nix')
+
+utils_gen = gen_header.process(meson.project_source_root() / 'doc/manual/utils.nix')
+
+nix_sources = files(
+  'add-to-store.cc',
+  'app.cc',
+  'build.cc',
+  'bundle.cc',
+  'cat.cc',
+  'copy.cc',
+  'daemon.cc',
+  'derivation-add.cc',
+  'derivation-show.cc',
+  'derivation.cc',
+  'develop.cc',
+  'diff-closures.cc',
+  'doctor.cc',
+  'dump-path.cc',
+  'edit.cc',
+  'eval.cc',
+  'flake.cc',
+  'fmt.cc',
+  'hash.cc',
+  'log.cc',
+  'ls.cc',
+  'main.cc',
+  'make-content-addressed.cc',
+  'nar.cc',
+  'optimise-store.cc',
+  'path-from-hash-part.cc',
+  'path-info.cc',
+  'ping-store.cc',
+  'prefetch.cc',
+  'profile.cc',
+  'realisation.cc',
+  'registry.cc',
+  'repl.cc',
+  'run.cc',
+  'search.cc',
+  'show-config.cc',
+  'sigs.cc',
+  'store-copy-log.cc',
+  'store-delete.cc',
+  'store-gc.cc',
+  'store-repair.cc',
+  'store.cc',
+  'upgrade-nix.cc',
+  'verify.cc',
+  'why-depends.cc',
+)
+
+nix = executable(
+  'nix',
+  nix_sources,
+  generate_manpage_gen,
+  utils_gen,
+  nix2_commands_sources,
+  dependencies : [
+    liblixcmd,
+    liblixutil,
+    liblixstore,
+    liblixexpr,
+    liblixfetchers,
+    liblixmain,
+    boehm,
+  ],
+)
Author	SHA1	Message	Date
puck	e425a1d18d	Import C bindings from NixOS/nix#8699 Co-authored-by: Yorick van Pelt <yorick@yorickvanpelt.nl> Co-authored-by: José Luis Lafuente <jose.lafuente@tweag.io> Change-Id: `I48aa262d880aa75aa5b230553f663c35c283d5f6`	2024-03-17 16:38:04 +00:00
puck	de17a2f0fa	libexpr: Lessen const bound on Value::listElems() const I do not like this being a requirement, but it is necessary to make the C api work with the least amount of ABI changes. listElems() const returns a constant pointer to N constant pointers of Value. This bound is lessened (within defined behavior) to a constant pointer to N mutable pointers of Value. The upstream reasoning behind this is reasonable enough, though I strongly distrust it. It might be better to drop the `const` off of the C ABI instead. Change-Id: `I8e750b086c1b8d13972aa748ce8f6139f6bcbadb`	2024-03-17 16:25:12 +00:00
puck	7f9e09a434	libexpr: rename parseSearchPath to SearchPath::parse This was never called?? Change-Id: `I5c1b3ce0d5479a638fda98467efb2f34faaac726`	2024-03-17 16:06:00 +00:00
puck	883d2ad4d2	libexpr: use std::function rather than C function pointers for primops In preparation for the C bindings, which use this. Change-Id: `Ic1c58998951e69e66a794976585a381754dfbbeb`	2024-03-17 16:04:36 +00:00
Qyriad	7acdcf5511	meson: better match autotools cxxflags Change-Id: `I667c8685b13b7bab91e281053f807a11616ae3d4`	2024-03-16 19:23:19 -06:00
Qyriad	f150b3f7f8	meson: migrate generated headers to a generator() object Change-Id: `Ie7b9cab4189825e8f02dfb39d298302bc36fcb61`	2024-03-15 18:55:59 -06:00
Qyriad	75f823f2e4	meson: fix libstore on linux Change-Id: `I95fef8e630575c970538d2d8ba4c91d16ae5f8ac`	2024-03-15 18:55:28 -06:00
Qyriad	6fb79d08ae	meson: getting the nix command building Change-Id: `If2f4a82b0d23a11a828bb4b305fabe4e30e1e91b`	2024-03-15 16:44:54 -06:00
Qyriad	557dc678fd	meson: we can now build libcmd! Change-Id: `I3506b3d599cd038020d208b899f81b7251932fd8`	2024-03-13 21:16:03 -06:00
Qyriad	f2113c2416	meson: we can now build libmain! Change-Id: `I2333a18d790df843d07163ff884c80095d89e0cc`	2024-03-13 21:08:34 -06:00
Qyriad	e30dac46fe	meson: we can now build libexpr! Change-Id: `I937a217fdcb5bd33491cc20f04a734e9d732d5e5`	2024-03-13 20:53:51 -06:00
Qyriad	1af43a19a2	meson: we can now build libfetchers! Change-Id: `Ic3a64bbc6bb1a77d01652f339f62b7f301e6e7dc`	2024-03-12 21:58:53 -06:00
Qyriad	e2310d7cb2	meson: we can now build libstore! Change-Id: `I615bba179ce445af42a631f3859ef46308af50e2`	2024-03-12 14:05:36 -06:00
Qyriad	8c54e1ac26	meson: can now build libutil! Change-Id: `I6088a5a68637e19f85fcb4660b03ed9d1fc5f3a1`	2024-03-12 07:19:52 -06:00
Qyriad	bace7379b7	meson: generate a config.h that works with the current build system Change-Id: `I578982fdfc34af1f24ad0c1335dcd7bdef01fd9d`	2024-03-09 20:29:51 -07:00
Qyriad	a98500320e	package: cleanup of all intermediaries Change-Id: `I0da5182de6b01c192cfcba407959d659d70c6dc9`	2024-03-09 15:51:31 -07:00
Qyriad	5afa84342c	package: migrate devShells Change-Id: `Ic63721667edd4bef79aa699a0de8411639e5159b`	2024-03-09 15:51:27 -07:00
Qyriad	2fe0b373e9	package: migrate internal-api-docs Change-Id: `I344d73a412c2c6e4bb2eb14bd4859056324f1ba7`	2024-03-09 15:51:24 -07:00
Qyriad	e14b56943d	package: migrate testNixVersions Change-Id: `I71845f8a6d7b77c3617d055e726ed4a28cd05fa3`	2024-03-09 15:51:20 -07:00
Qyriad	1b8f5bb870	package: use pname, version, and doBuild (first change with diff hash) The src fileset, preConfigure, and separateDebugInfo also respond to doBuild if its overridden This commit is logically just a continuation of the previous commit's refactor, but exists separately to delineate when the core Nix derivation hash changed (this commit). Change-Id: `I67a61bc9608d91b6a833ebc5c3894b2d2e694050`	2024-03-09 15:51:16 -07:00
Qyriad	f8efdea4a2	package: refactor Nix out of flake.nix and into package.nix This series takes a somewhat different approach from the flake rework done in NixOS/nix. The package.nix here does not provide callPackage options for all the various settings in the build, and instead the other places Nix derivations are used (like internal-api-docs) will .overrideAttrs the normal Nix package derivation. This more closely matches how these things were structured originally, and results in less churn and more atomicity in these changes. In the future, package.nix likely will migrate to have more build options in the callPackage arguments, but we are also planning to rewrite the build system anyway. Change-Id: `I170c4e5a4184bab62e1fd75e56db876d4ff116cf`	2024-03-09 15:48:16 -07:00