diff --git a/src/nix/repl.cc b/src/nix/repl.cc index a992d8732..bce8d31dc 100644 --- a/src/nix/repl.cc +++ b/src/nix/repl.cc @@ -405,6 +405,7 @@ bool NixRepl::processLine(string line) } if (command == ":?" || command == ":help") { + // FIXME: convert to Markdown, include in the 'nix repl' manpage. std::cout << "The following commands are available:\n" << "\n" @@ -801,14 +802,11 @@ struct CmdRepl : StoreCommand, MixEvalArgs return "start an interactive environment for evaluating Nix expressions"; } - Examples examples() override + std::string doc() override { - return { - Example{ - "Display all special commands within the REPL:", - "nix repl\nnix-repl> :?" - } - }; + return + #include "repl.md" + ; } void run(ref<Store> store) override diff --git a/src/nix/repl.md b/src/nix/repl.md new file mode 100644 index 000000000..bba60f871 --- /dev/null +++ b/src/nix/repl.md @@ -0,0 +1,57 @@ +R""( + +# Examples + +* Display all special commands within the REPL: + + ```console + # nix repl + nix-repl> :? + ``` + +* Evaluate some simple Nix expressions: + + ```console + # nix repl + + nix-repl> 1 + 2 + 3 + + nix-repl> map (x: x * 2) [1 2 3] + [ 2 4 6 ] + ``` + +* Interact with Nixpkgs in the REPL: + + ```console + # nix repl '<nixpkgs>' + + Loading '<nixpkgs>'... + Added 12428 variables. + + nix-repl> emacs.name + "emacs-27.1" + + nix-repl> emacs.drvPath + "/nix/store/lp0sjrhgg03y2n0l10n70rg0k7hhyz0l-emacs-27.1.drv" + + nix-repl> drv = runCommand "hello" { buildInputs = [ hello ]; } "hello > $out" + + nix-repl> :b x + this derivation produced the following outputs: + out -> /nix/store/0njwbgwmkwls0w5dv9mpc1pq5fj39q0l-hello + + nix-repl> builtins.readFile drv + "Hello, world!\n" + ``` + +# Description + +This command provides an interactive environment for evaluating Nix +expressions. (REPL stands for 'read–eval–print loop'.) + +On startup, it loads the Nix expressions named *files* and adds them +into the lexical scope. You can load addition files using the `:l +<filename>` command, or reload all files using `:r`. + +)""