Commit graph

292 commits

Author SHA1 Message Date
Eelco Dolstra 1a7e88bbd9 * New built-in function `builtins.attrNames' that returns the
names of the attributes in an attribute set.
2006-12-12 16:14:31 +00:00
Eelco Dolstra fcd9900d74 * Replace read-only calls to addTextToStore. 2006-12-01 21:00:39 +00:00
Eelco Dolstra 6ecb840fd1 * Put building in the store API. 2006-11-30 18:02:04 +00:00
Eelco Dolstra e2ef5e07fd * Refactoring. There is now an abstract interface class StoreAPI
containing functions that operate on the Nix store.  One
  implementation is LocalStore, which operates on the Nix store
  directly.  The next step, to enable secure multi-user Nix, is to
  create a different implementation RemoteStore that talks to a
  privileged daemon process that uses LocalStore to perform the actual
  operations.
2006-11-30 17:43:04 +00:00
Eelco Dolstra 7e85a2af5f * Fix importing of derivation outputs. 2006-11-03 16:17:39 +00:00
Eelco Dolstra dd300fb48d * Some better error messages. 2006-10-23 16:45:19 +00:00
Eelco Dolstra 17f4883bfe * Better message. 2006-10-19 17:43:58 +00:00
Eelco Dolstra 9bd93f7606 * toFile: maintain the references. 2006-10-19 17:39:02 +00:00
Eelco Dolstra 3059df0f1e * baseNameOf: paths don't have to be absolute. 2006-10-17 12:34:13 +00:00
Eelco Dolstra be1961c9f8 * toPath: should be the identity on paths. 2006-10-17 11:07:11 +00:00
Eelco Dolstra cba913c521 * dirOf: return a path if the argument is a path. 2006-10-17 11:05:34 +00:00
Eelco Dolstra cf705eaf78 * toString: don't copy paths. So toString can be used to pass
non-store paths to a builder.
2006-10-17 10:58:12 +00:00
Eelco Dolstra d7efd76394 * Big cleanup of the semantics of paths, strings, contexts, string
concatenation and string coercion.  This was a big mess (see
  e.g. NIX-67).  Contexts are now folded into strings, so that they
  don't cause evaluation errors when they're not expected.  The
  semantics of paths has been clarified (see nixexpr-ast.def).
  toString() and coerceToString() have been merged.

  Semantic change: paths are now copied to the store when they're in a
  concatenation (and in most other situations - that's the
  formalisation of the meaning of a path).  So

    "foo " + ./bla

  evaluates to "foo /nix/store/hash...-bla", not "foo
  /path/to/current-dir/bla".  This prevents accidental impurities, and
  is more consistent with the treatment of derivation outputs, e.g.,
  `"foo " + bla' where `bla' is a derivation.  (Here `bla' would be
  replaced by the output path of `bla'.)
2006-10-16 15:55:34 +00:00
Eelco Dolstra 7d4567f2cc * Removed URIs from the evaluator (NIX-66). They are now just another
kind of notation for strings.
2006-10-11 21:59:33 +00:00
Eelco Dolstra 0c4c5c2020 * Quick hack to fix NIX-67: evaluation result differing if the Nix
expression resides in the store.
2006-10-10 21:23:35 +00:00
Eelco Dolstra bd0c40e1e9 * import': unwrap the context. Necessary to make import (x + y)'
work, where x is a store path.
2006-10-10 15:07:23 +00:00
Eelco Dolstra 5fd44654db * toXML: propagate the context to allow derivations to be used in the
argument.
2006-10-03 15:38:59 +00:00
Eelco Dolstra d20c3011a0 * toFile: added an additional argument to specify the store path
suffix, e.g., `builtins.toFile "builder.sh" "..."'.
* toFile: handle references to other files correctly.
2006-10-03 14:55:54 +00:00
Eelco Dolstra e347033f71 * The result of a concatenation with a derivation on the left-hand
side should be a path, I guess.
* Handle paths that are in the store but not direct children of the
  store directory.
* Ugh, hack to prevent double context wrapping.
2006-09-24 21:39:57 +00:00
Eelco Dolstra 0e705391db * Primop `toPath' to convert a string to a path.
* Primop `pathExists' to check for path existence.
2006-09-24 18:23:32 +00:00
Eelco Dolstra e47e0c2dbe * Builtin function `getEnv' for getting environment variables. 2006-09-24 17:48:41 +00:00
Eelco Dolstra df8873e14a * lessThan primitive for integer comparison. 2006-09-24 15:21:48 +00:00
Eelco Dolstra 2ab4bc44c7 * Builtin function `add' to add integers.
* Put common test functions in tests/lang/lib.nix.
2006-09-22 15:29:21 +00:00
Eelco Dolstra d315210612 * Added a builtin function `isList' to test whether a value is a list.
With this primitive, a list-flattening function can be implemented
  (NIX-55, example is in tests/lang/eval-okay-flatten.nix).
2006-09-22 14:55:19 +00:00
Eelco Dolstra c02a44183f * Builtin functions head' and tail' to return the head and tail of
list.  Useful for lots of things, such as implementing a fold
  function (see NIX-30, example is in tests/lang/eval-okay-list.nix).
2006-09-22 14:46:36 +00:00
Eelco Dolstra 8a1ab709a4 * New builtin functions builtins.{hasAttr, getAttr} to check for
attribute existence and to return an attribute from an attribute
  set, respectively.  Example: `hasAttr "foo" {foo = 1;}'.  They
  differ from the `?' and `.' operators in that the attribute name is
  an arbitrary expression.  (NIX-61)
2006-09-22 14:31:55 +00:00
Eelco Dolstra 4e91d8621f * Fix comment. 2006-09-21 18:52:05 +00:00
Eelco Dolstra 0623359fbc * Print a better error message for wrong hashes (NIX-49). 2006-09-20 16:15:32 +00:00
Eelco Dolstra 75068e7d75 * Use a proper namespace.
* Optimise header file usage a bit.
* Compile the parser as C++.
2006-09-04 21:06:23 +00:00
Eelco Dolstra 7974aae81c * New primop: builtins.toFile, which writes a string into the store
and returns its path.  This can be used to (for instance) write
  builders inside a Nix expression, e.g.,

  stdenv.mkDerivation {
    builder = "
      source $stdenv/setup
      ...
    ";
    ...
  }
2006-09-01 12:07:31 +00:00
Eelco Dolstra 547b119f25 * Support singleton values and nested lists again in `args', but print
a warning.
2006-08-29 15:40:49 +00:00
Eelco Dolstra 2132d9ddeb * Fix the ~ operator. 2006-08-29 15:29:38 +00:00
Eelco Dolstra 1ec9f55741 * In toString, deal with nested lists properly (i.e., flatten them). 2006-08-28 21:47:42 +00:00
Eelco Dolstra 1fca76870b * Removed processBinding, instead we now apply toString to all
derivation attributes to flatten them into strings.  This is
  possible since string can nowadays be wrapped in contexts that
  describe the derivations/sources referenced by the evaluation of the
  string.
2006-08-28 13:31:06 +00:00
Eelco Dolstra 8a6080eb14 * Refactoring. 2006-08-26 16:48:01 +00:00
Eelco Dolstra 4b66cebe7b * Remove those storePath attribute sets, we don't need 'em. 2006-08-25 17:09:55 +00:00
Eelco Dolstra 215ec2ddc6 * New primop __toXML (or builtins.toXML) to convert an expression to
an XML representation stored in a string.  This should be useful to
  pass structured information to builders.
2006-08-24 14:34:29 +00:00
Eelco Dolstra b19cebc513 * Quotes. 2006-08-23 15:46:27 +00:00
Eelco Dolstra 38f18aa6d4 * New primop: abort "error message". 2006-08-23 15:46:00 +00:00
Eelco Dolstra 4a053bfdfd * A new primop `builtins', which returns an attribute set containing
all the primops.  This allows Nix expressions to test for new
  primops and take appropriate action if they're not available.  For
  instance, rather than calling a primop `foo' directly, they could
  say `if builtins ? foo then builtins.foo ... else ...'.
2006-08-23 14:39:11 +00:00
Eelco Dolstra a18d02e0b0 * Print a warning that the subpath operator (~) is deprecated. 2006-08-09 15:08:47 +00:00
Eelco Dolstra 4f3725b167 * Better error messages (especially wrt types). 2006-07-19 15:36:15 +00:00
Eelco Dolstra 9d72bf8835 * 64-bit compatibility fixes (for problems revealed by building on an Athlon
64 running 64-bit SUSE).  A patched ATerm library is required to run Nix
  succesfully.
2006-05-11 02:19:43 +00:00
Eelco Dolstra 0832956089 * Use the new ATermMap. 2006-05-04 12:21:08 +00:00
Eelco Dolstra 6cecad2be0 * Allow string concatenations involving derivations, e.g.,
configureFlags = "--with-freetype2-library="
      + freetype + "/lib";
2006-05-01 09:56:56 +00:00
Eelco Dolstra ef2d4a2da9 * Print a more useful stack trace when an error occurs deep in the
derivation dependency graph.
2006-03-24 14:02:44 +00:00
Eelco Dolstra 37d1b1cafd * `nix-env -qa --description' shows human-readable descriptions of
packages (provided that they have a `meta.description' attribute).
  E.g.,

  $ ./src/nix-env/nix-env -qa --description gcc
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for sparc-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for mips-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for arm-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x
2006-03-10 16:20:42 +00:00
Eelco Dolstra 922697c8b2 * Big speedup (factor > 2.5) in all nix-env operations that do actual
instantiation, e.g. "nix-env -i" and "nix-env -qas" (but not
  "nix-env -qa").  It turns out that many redundant calls to
  addToStore(path) were made, which reads and hashes the entire path.
  For instance, the bash bootstrap binary in Nixpkgs would be read and
  hashed many times.  As a result nix-env would spend around 92% of
  its time in the function sha256_block (according to callgrind).
  Some simple memoization fixes this.
2006-03-09 15:09:18 +00:00
Eelco Dolstra 9088dee9e2 * Some refactoring of the exception handling code so that we can catch
Nix expression assertion failures.
2006-03-08 14:11:19 +00:00
Eelco Dolstra c8bfb11b34 * `nix-env (-i|-u) --dry-run' now shows exactly which missing paths
will be built or substituted.
2006-03-06 11:21:15 +00:00
Eelco Dolstra cf2bb91ec8 * Missing #include. 2005-09-13 13:17:01 +00:00
Eelco Dolstra e1a6fb7870 * `dependencyClosure' now allows a search path, e.g.,
dependencyClosure { ... searchPath = [ ../foo ../bar ]; ... }

* Primop `dirOf' to return the directory part of a path (e.g., dirOf
  /a/b/c == /a/b).

* Primop `relativise' (according to Webster that's a real word!) that
  given paths A and B returns a string representing path B relative
  path to A; e.g., relativise /a/b/c a/b/x/y => "../x/y".
2005-08-14 14:00:39 +00:00
Eelco Dolstra 08c53923db * A primitive operation `dependencyClosure' to do automatic dependency
determination (e.g., finding the header files dependencies of a C
  file) in Nix low-level builds automatically.

  For instance, in the function `compileC' in make/lib/default.nix, we
  find the header file dependencies of C file `main' as follows:

    localIncludes =
      dependencyClosure {
        scanner = file:
          import (findIncludes {
            inherit file;
          });
        startSet = [main];
      };

  The function works by "growing" the set of dependencies, starting
  with the set `startSet', and calling the function `scanner' for each
  file to get its dependencies (which should yield a list of strings
  representing relative paths).  For instance, when `scanner' is
  called on a file `foo.c' that includes the line

    #include "../bar/fnord.h"

  then `scanner' should yield ["../bar/fnord.h"].  This list of
  dependencies is absolutised relative to the including file and added
  to the set of dependencies.  The process continues until no more
  dependencies are found (hence its a closure).

  `dependencyClosure' yields a list that contains in alternation a
  dependency, and its relative path to the directory of the start
  file, e.g.,

    [ /bla/bla/foo.c
      "foo.c"
      /bla/bar/fnord.h
      "../bar/fnord.h"
    ]

  These relative paths are necessary for the builder that compiles
  foo.c to reconstruct the relative directory structure expected by
  foo.c.

  The advantage of `dependencyClosure' over the old approach (using
  the impure `__currentTime') is that it's completely pure, and more
  efficient because it only rescans for dependencies (i.e., by
  building the derivations yielded by `scanner') if sources have
  actually changed.  The old approach rescanned every time.
2005-08-14 12:38:47 +00:00
Eelco Dolstra 991a130b1e * Added a list concatenation operator:
[1 2 3] ++ [4 5 6] => [1 2 3 4 5 6]
2005-07-25 15:05:34 +00:00
Eelco Dolstra 040140dd1c * Added a primop `removeAttrs' to remove attributes from a set, e.g.,
`removeAttrs attrs ["x", "y"]' returns the set `attrs' with the
  attributes named `x' and `y' removed.  It is not an error for the
  named attributes to be missing from the input set.
2005-05-18 17:19:21 +00:00
Eelco Dolstra 77557a6f06 Commit 3000!
* Make the `derivation' primitive much more lazy.  The expression
  `derivation attrs' now evaluates to (essentially)

    attrs // {
      type = "derivation";
      outPath = derivation! attrs;
      drvPath = derivation! attrs;
    }

  where `derivation!' is a primop that does the actual derivation
  instantiation (i.e., it does what `derivation' used to do).  The
  advantage is that it allows commands such as `nix-env -qa' and
  `nix-env -i' to be much faster since they no longer need to
  instantiate all derivations, just the `name' attribute.  (However,
  `nix-env' doesn't yet take advantage of this since it still always
  evaluates the `outPath' and `drvPath' attributes).

  Also, this allows derivations to cyclically reference each other,
  for example,

    webServer = derivation {
      ...
      hostName = "svn.cs.uu.nl";
      services = [svnService];
    };

    svnService = derivation {
      ...
      hostName = webServer.hostName;
    };

  Previously, this would yield a black hole (infinite recursion).
2005-05-07 21:48:49 +00:00
Eelco Dolstra 02f2da0142 * Merging from nix-make branch:
- Add __currentTime primitive (dangerous!).
  - Allow imports of derivations.
2005-05-02 14:44:58 +00:00
Eelco Dolstra c9c58dba55 * Primop `__currentSystem' to return the current platform identifier. 2005-04-10 17:38:19 +00:00
Eelco Dolstra 10c429c757 * If store paths are specified as sources in Nix expressions, don't
copy them, but use them directly.
2005-04-07 14:35:01 +00:00
Eelco Dolstra c815aff21b * `nix-store --add-fixed' to preload the outputs of fixed-output
derivations.  This is mostly to simplify the implementation of
  nix-prefetch-{url, svn}, which now work properly in setuid
  installations.

* Enforce valid store names in `nix-store --add / --add-fixed'.
2005-04-07 14:01:51 +00:00
Eelco Dolstra 3a2c3f0cf2 * Support for fixed-output hashes over directory trees (i.e., over the
NAR dump of the path).
2005-02-22 21:14:41 +00:00
Eelco Dolstra 20ce2642fc * Refactoring to support different installation sources in nix-env.
* Set the references for the user environment manifest properly.
* Don't copy the manifest (this was accidental).
* Don't store derivation paths in the manifest (maybe this should be
  made optional).  This cleans up the semantics of nix-env, which were
  weird.
* Hash on the output paths of activated components, not on derivation
  paths.  This is because we don't know the derivation path of already
  installed components anymore, and it allows the installation of
  components by store path (skipping Nix expressions entirely).
* Query options `--out-path' and `--drv-path' to show the output and
  derivation paths of components, respectively (the latter replaces
  the `--expr' query).
2005-02-11 16:56:45 +00:00
Eelco Dolstra 6bb5efadec * Ensure that derivation names and sources don't end in `.drv'. 2005-01-20 15:25:01 +00:00
Eelco Dolstra 05f0430de1 * Another change to low-level derivations. The last one this year, I
promise :-) This allows derivations to specify on *what* output
  paths of input derivations they are dependent.  This helps to
  prevent unnecessary downloads.  For instance, a build might be
  dependent on the `devel' and `lib' outputs of some library
  component, but not the `docs' output.
2005-01-20 14:10:19 +00:00
Eelco Dolstra 96de272b48 * Renamed normalise.cc' -> build.cc', `storeexprs.cc' ->
`derivations.cc', etc.
* Store the SHA-256 content hash of store paths in the database after
  they have been built/added.  This is so that we can check whether
  the store has been messed with (a la `rpm --verify').
* When registering path validity, verify that the closure property
  holds.
2005-01-19 16:39:47 +00:00
Eelco Dolstra 06c77bf7a8 * Change extension .store' to .drv'.
* Re-enable `nix-store --query --requisites'.
2005-01-19 14:36:00 +00:00
Eelco Dolstra 863dcff6c5 * Started removing closure store expressions, i.e., the explicit
representation of closures as ATerms in the Nix store.  Instead, the
  file system pointer graph is now stored in the Nix database.  This
  has many advantages:

  - It greatly simplifies the implementation (we can drop the notion
    of `successors', and so on).

  - It makes registering roots for the garbage collector much easier.
    Instead of specifying the closure expression as a root, you can
    simply specify the store path that must be retained as a root.
    This could not be done previously, since there was no way to find
    the closure store expression containing a given store path.
    
  - Better traceability: it is now possible to query what paths are
    referenced by a path, and what paths refer to a path.
2005-01-19 11:16:11 +00:00
Eelco Dolstra 6d493751c3 * Get --readonly-mode to work again. 2005-01-18 11:15:50 +00:00
Eelco Dolstra f3dc231250 * Removed the `id' attribute hack.
* Formalise the notion of fixed-output derivations, i.e., derivations
  for which a cryptographic hash of the output is known in advance.
  Changes to such derivations should not propagate upwards through the
  dependency graph.  Previously this was done by specifying the hash
  component of the output path through the `id' attribute, but this is
  insecure since you can lie about it (i.e., you can specify any hash
  and then produce a completely different output).  Now the
  responsibility for checking the output is moved from the builder to
  Nix itself.

  A fixed-output derivation can be created by specifying the
  `outputHash' and `outputHashAlgo' attributes, the latter taking
  values `md5', `sha1', and `sha256', and the former specifying the
  actual hash in hexadecimal or in base-32 (auto-detected by looking
  at the length of the attribute value).  MD5 is included for
  compatibility but should be considered deprecated.

* Removed the `drvPath' pseudo-attribute in derivation results.  It's
  no longer necessary.

* Cleaned up the support for multiple output paths in derivation store
  expressions.  Each output now has a unique identifier (e.g., `out',
  `devel', `docs').  Previously there was no way to tell output paths
  apart at the store expression level.

* `nix-hash' now has a flag `--base32' to specify that the hash should
  be printed in base-32 notation.

* `fetchurl' accepts parameters `sha256' and `sha1' in addition to
  `md5'.

* `nix-prefetch-url' now prints out a SHA-1 hash in base-32.  (TODO: a
  flag to specify the hash.)
2005-01-17 16:55:19 +00:00
Eelco Dolstra d58a11e019 * Shorten SHA-256 hashes used in store path name generation to 160
bits, then encode them in a radix-32 representation (using digits
  and letters except e, o, u, and t).  This produces store paths like
  /nix/store/4i0zb0z7f88mwghjirkz702a71dcfivn-aterm-2.3.1.  The nice
  thing about this is that the hash part of the file name is still 32
  characters, as before with MD5.

  (Of course, shortening SHA-256 to 160 bits makes it no better than
  SHA-160 in theory, but hopefully it's a bit more resistant to
  attacks; it's certainly a lot slower.)
2005-01-14 16:04:03 +00:00
Eelco Dolstra 9530cc3170 * Start move towards SHA-256 hashes instead of MD5.
* Start cleaning up unique store path generation (they weren't always
  unique; in particular the suffix ("-aterm-2.2", "-builder.sh") was
  not part of the hash, therefore changes to the suffix would cause
  multiple store objects with the same hash).
2005-01-14 13:51:38 +00:00
Eelco Dolstra 7e8961f720 * Added SHA-1 support. nix-hash' now has an option --type sha1' to
select SHA-1 hashing.
2005-01-13 17:39:26 +00:00
Eelco Dolstra 73992371a3 * Refactoring to support SHA-1. 2005-01-13 15:44:44 +00:00
Eelco Dolstra cb7ccb528b * string2ATerm -> overloaded toATerm. 2004-11-03 18:12:03 +00:00
Eelco Dolstra a69534fc21 * Drop ATmake / ATMatcher also in handling store expressions. 2004-10-29 11:22:49 +00:00
Eelco Dolstra 5fe9222b36 * Don't use ATmake / ATmatch anymore, nor the ATMatcher class.
Instead we generate data bindings (build and match functions) for
  the constructors specified in `constructors.def'.  In particular
  this removes the conversions between AFuns and strings, and Nix
  expression evaluation now seems 3 to 4 times faster.
2004-10-26 22:54:26 +00:00
Eelco Dolstra eb8284ddaa * Evaluate argument to `import'. 2004-10-26 17:10:09 +00:00
Eelco Dolstra 9fa07b376d * String/path concatenation operator (`+'). 2004-10-26 17:01:35 +00:00
Eelco Dolstra 37d7abd694 * New language feature: with expressions.
The expression `with E1; E2' evaluates to E2 with all bindings in
  the attribute set E1 substituted.  E.g.,

    with {x = 123;}; x

  evaluates to 123.  That is, the attribute set E1 is in scope in E2.

  This is particularly useful when importing files containing lots
  definitions.  E.g., instead of

    let {
      inherit (import ./foo.nix) a b c d e f;

      body = ... a ... f ...;
    }

  we can now say

    with import ./foo.nix;

    ... a ... f ...

  I.e., we don't have to say what variables should be brought into scope.
2004-10-25 16:54:56 +00:00
Eelco Dolstra f4d44a0026 * Allow certain operations to succeed even if we don't have write
permission to the Nix store or database.  E.g., `nix-env -qa' will
  work, but `nix-env -qas' won't (the latter needs DB access).  The
  option `--readonly-mode' forces this mode; otherwise, it's only
  activated when the database cannot be opened.
2004-10-25 14:38:23 +00:00
Eelco Dolstra 9994c1dd9f * Validate derivation names. In particular don't allow spaces.
* Drop support for the outPath attribute in derivations.
2004-08-24 11:46:05 +00:00
Eelco Dolstra d8989b1fb4 * Every real language has a `map' function. 2004-08-04 11:27:53 +00:00
Eelco Dolstra bbfdd64741 * Allow primops with more that 1 arguments. 2004-08-04 10:59:20 +00:00
Eelco Dolstra 59b94ee18a * When something goes wrong in the evaluation of a Nix expression,
print a nice backtrace of the stack, rather than vomiting a gigantic
  (and useless) aterm on the screen.  Example:

    error: while evaluating file `.../pkgs/system/test.nix':
    while evaluating attribute `subversion' at `.../pkgs/system/all-packages-generic.nix', line 533:
    while evaluating function at `.../pkgs/applications/version-management/subversion/default.nix', line 1:
    assertion failed at `.../pkgs/applications/version-management/subversion/default.nix', line 13

  Since the Nix expression language is lazy, the trace may be
  misleading.  The purpose is to provide a hint as to the location of
  the problem.
2004-04-05 22:27:41 +00:00
Eelco Dolstra a520b1cbc3 * Print a more useful error message in case of an invalid derivation
binding.
2004-04-02 10:49:37 +00:00
Eelco Dolstra f958bcdf1f * Added an operator `~' to select paths within a derivation. E.g.,
{stdenv, bash}: derivation {
      builder = bash ~ /bin/sh;
      args = ["-e" "-x" ./builder.sh];
      ...
    }

  Here the attribute `builder' will evaluate to, e.g.,
  `/nix/store/1234abcd...-bash-2.0.1/bin/sh'.
2004-03-28 20:58:28 +00:00
Eelco Dolstra db3e644c1c * Added plain lambdas, e.g., `let { id = x: x; const = x: y: x; }'.
`bla:' is now no longer parsed as a URL.

* Re-enabled support for the `args' attribute in derivations to
  specify command line arguments to the builder, e.g.,

    ...
    builder = /usr/bin/python;
    args = ["-c" ./builder.py];
    ...
2004-03-28 20:34:22 +00:00
Eelco Dolstra 9b44480612 * Use a map to lookup primops.
* Various performance improvements in the evaluator.
* Do not link against unused (and missing!) libraries (-lsglr, etc.).
2004-02-04 16:03:29 +00:00
Eelco Dolstra 1c9c0a5a46 * Added syntactic sugar to the construction of attribute sets to
`inherit' variables from the surrounding lexical scope.

  E.g.,

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      inherit stdenv libfoo;
      xyzzy = 1;
    }

  is equivalent to

    {stdenv, libfoo}: derivation {
      builder = ./bla;
      stdenv = stdenv;
      libfoo = libfoo;
      xyzzy = 1;
    }

  Note that for mutually recursive attribute set definitions (`rec
  {...}'), this also works, that is, `rec {inherit x;}' is equivalent
  to `let {fresh = x; body = rec {x = fresh;};}', *not*
  `rec {x = x}'.
2004-02-02 21:39:33 +00:00
Eelco Dolstra 6e8c19714a * Allow integer bindings in derivations. 2003-11-25 12:05:48 +00:00
Eelco Dolstra 06208d1d86 * Uninstallation. 2003-11-21 14:23:18 +00:00
Eelco Dolstra ac68840e79 * Refactoring: put the Nix expression evaluator in its own library so
that it can be used by multiple programs.
2003-11-19 11:35:41 +00:00
Renamed from src/nix-instantiate/primops.cc (Browse further)