Commit graph

198 commits

Author SHA1 Message Date
Eelco Dolstra f134fc4cbe
Document that builtins.match takes a POSIX extended RE 2017-05-17 12:18:18 +02:00
Guillaume Maudoux a474425425 Fix lexer to support $' in multiline strings. 2017-05-01 01:15:40 +02:00
Guillaume Maudoux e4b82af387 Improve error message on trailing path slashes 2016-11-27 17:48:46 +01:00
Guillaume Maudoux a5e761dddb Fix comments parsing
Fixed the parsing of multiline strings ending with an even number of
stars, like /** this **/.
Added test cases for comments.
2016-11-13 17:20:34 +01:00
Eelco Dolstra 26d92017d3 Add builtin function "partition"
The implementation of "partition" in Nixpkgs is O(n^2) (because of the
use of ++), and for some reason was causing stack overflows in
multi-threaded evaluation (not sure why).

This reduces "nix-env -qa --drv-path" runtime by 0.197s and memory
usage by 298 MiB (in non-Boehm mode).
2016-08-29 19:36:54 +02:00
Eelco Dolstra e03d6e0998 Fix broken number parsing in fromJSON
The call to tmp_number.append had its arguments mixed up. Also, JSON
does not allow a trailing "," after array/object members.
2016-02-15 15:01:26 +01:00
Eelco Dolstra eb62e23f14 Fix test broken by #762 2016-02-15 15:01:26 +01:00
Eelco Dolstra b3e8d72770 Merge pull request #762 from ctheune/ctheune-floats
Implement floats
2016-02-12 12:49:59 +01:00
Eelco Dolstra 4f7824c58e Remove tests/lexer.sh
"tests/lang.sh" can handle this.
2016-02-01 18:27:37 +01:00
Christian Theune 5cdcaf5e8e Adapt tests to show that floats work properly. 2016-01-06 10:03:24 +01:00
Eelco Dolstra 6f1743b1a5 Support SHA-512 hashes
Fixes #679.

Note: on x86_64, SHA-512 is considerably faster than SHA-256 (198 MB/s
versus 131 MB/s).
2015-11-04 16:37:49 +01:00
Eelco Dolstra 76cc8e97a2 Add sort primop 2015-07-28 18:39:39 +02:00
Eelco Dolstra 50807f3dd5 Add primop genList
This can be used to implement functions like ‘imap’ (or for that
matter, ‘map’) without the quadratic complexity incurred by calling
‘++’ repeatedly.
2015-07-28 17:28:35 +02:00
Eelco Dolstra d6d5885c15 Add replaceStrings primop
This is a generalisation of replaceChars in Nixpkgs.
2015-07-24 15:32:24 +02:00
Eelco Dolstra 2e8fd4c5cd Add concatStringsSep as a primop
This fixes the quadratic behaviour of concatStrings/concatStringsSep
in Nixpkgs.
2015-07-24 02:38:09 +02:00
Eelco Dolstra 14be783676 Add primops all and any
These are used thousands of times during NixOS evaluation, so it's
useful to speed them up.
2015-07-23 19:23:11 +02:00
Eelco Dolstra 61af14a921 Add foldl' primop 2015-07-23 17:03:02 +02:00
Guillaume Maudoux 467977f203 Fix the parsing of "$"'s in strings. 2015-07-03 14:09:58 +02:00
Shea Levy 73bf32ce94 Merge remote-tracking branch 'shlevy/baseNameOf-no-copy'
baseNameOf: Don't copy paths to the store first
2015-01-29 03:29:09 -05:00
Eelco Dolstra 976df480c9 Add a primop for regular expression pattern matching
The function ‘builtins.match’ takes a POSIX extended regular
expression and an arbitrary string. It returns ‘null’ if the string
does not match the regular expression. Otherwise, it returns a list
containing substring matches corresponding to parenthesis groups in
the regex. The regex must match the entire string (i.e. there is an
implied "^<pat>$" around the regex).  For example:

  match "foo" "foobar" => null
  match "foo" "foo" => []
  match "f(o+)(.*)" "foooobar" => ["oooo" "bar"]
  match "(.*/)?([^/]*)" "/dir/file.nix" => ["/dir/" "file.nix"]
  match "(.*/)?([^/]*)" "file.nix" => [null "file.nix"]

The following example finds all regular files with extension .nix or
.patch underneath the current directory:

  let

    findFiles = pat: dir: concatLists (mapAttrsToList (name: type:
      if type == "directory" then
        findFiles pat (dir + "/" + name)
      else if type == "regular" && match pat name != null then
        [(dir + "/" + name)]
      else []) (readDir dir));

  in findFiles ".*\\.(nix|patch)" (toString ./.)
2014-11-25 11:47:06 +01:00
Shea Levy 997defa166 Add functors (callable attribute sets).
With this, attribute sets with a `__functor` attribute can be applied
just like normal functions. This can be used to attach arbitrary
metadata to a function without callers needing to treat it specially.
2014-11-15 16:12:05 -05:00
Shea Levy c9bd6a1de4 Fix context test 2014-10-18 20:34:48 -04:00
Eelco Dolstra c3f0a489f9 Add primop ‘catAttrs’ 2014-10-04 18:15:03 +02:00
Eelco Dolstra d4fcbe1687 Add primop ‘attrValues’ 2014-10-04 16:41:24 +02:00
Shea Levy 3fd2d2187e Add test for readDir primop 2014-10-03 22:32:11 +02:00
Eelco Dolstra 0cd6596b0e Add ‘deepSeq’ primop
Note that unlike ‘lib.deepSeq’ in Nixpkgs, this handles cycles.
2014-09-22 16:05:00 +02:00
Eelco Dolstra a54c263402 Add ‘seq’ primop 2014-09-22 16:05:00 +02:00
Eelco Dolstra 3d221a7bb1 Rename nixPath to __nixPath
The name ‘nixPath’ breaks existing code.
2014-07-30 11:28:39 +02:00
Eelco Dolstra beaf3e90af Add builtin function ‘fromJSON’
Fixes #294.
2014-07-04 13:34:15 +02:00
Eelco Dolstra ee7fe64c0a == operator: Ignore string context
There really is no case I can think of where taking the context into
account is useful. Mostly it's just very inconvenient.
2014-06-10 14:02:56 +02:00
Eelco Dolstra ceed819284 Fix test 2014-05-29 19:04:27 +02:00
Eelco Dolstra 62a6eeb1f3 Make the Nix search path declarative
Nix search path lookups like <nixpkgs> are now desugared to ‘findFile
nixPath <nixpkgs>’, where ‘findFile’ is a new primop. Thus you can
override the search path simply by saying

  let
    nixPath = [ { prefix = "nixpkgs"; path = "/my-nixpkgs"; } ];
  in ... <nixpkgs> ...

In conjunction with ‘scopedImport’ (commit
c273c15cb1), the Nix search path can be
propagated across imports, e.g.

  let

    overrides = {
      nixPath = [ ... ] ++ builtins.nixPath;
      import = fn: scopedImport overrides fn;
      scopedImport = attrs: fn: scopedImport (overrides // attrs) fn;
      builtins = builtins // overrides;
    };

  in scopedImport overrides ./nixos
2014-05-26 17:02:22 +02:00
Eelco Dolstra 39d72640c2 Ensure that -I flags get included in nixPath
Also fixes #261.
2014-05-26 16:52:31 +02:00
Eelco Dolstra a8edf185a9 Add constant ‘nixPath’
It contains the Nix expression search path as a list of { prefix, path
} sets, e.g.

  [ { path = "/nix/var/nix/profiles/per-user/root/channels/nixos"; prefix = ""; }
    { path = "/etc/nixos/configuration.nix"; prefix = "nixos-config"; }
    { path = "/home/eelco/Dev/nix/inst/share/nix/corepkgs"; prefix = "nix"; }
  ]
2014-05-26 14:55:47 +02:00
Eelco Dolstra c273c15cb1 Add primop ‘scopedImport’
‘scopedImport’ works like ‘import’, except that it takes a set of
attributes to be added to the lexical scope of the expression,
essentially extending or overriding the builtin variables.  For
instance, the expression

  scopedImport { x = 1; } ./foo.nix

where foo.nix contains ‘x’, will evaluate to 1.

This has a few applications:

* It allows getting rid of function argument specifications in package
  expressions. For instance, a package expression like:

    { stdenv, fetchurl, libfoo }:

    stdenv.mkDerivation { ... buildInputs = [ libfoo ]; }

  can now we written as just

    stdenv.mkDerivation { ... buildInputs = [ libfoo ]; }

  and imported in all-packages.nix as:

    bar = scopedImport pkgs ./bar.nix;

  So whereas we once had dependencies listed in three places
  (buildInputs, the function, and the call site), they now only need
  to appear in one place.

* It allows overriding builtin functions. For instance, to trace all
  calls to ‘map’:

  let
    overrides = {
      map = f: xs: builtins.trace "map called!" (map f xs);

      # Ensure that our override gets propagated by calls to
      # import/scopedImport.
      import = fn: scopedImport overrides fn;

      scopedImport = attrs: fn: scopedImport (overrides // attrs) fn;

      # Also update ‘builtins’.
      builtins = builtins // overrides;
    };
  in scopedImport overrides ./bla.nix

* Similarly, it allows extending the set of builtin functions. For
  instance, during Nixpkgs/NixOS evaluation, the Nixpkgs library
  functions could be added to the default scope.

There is a downside: calls to scopedImport are not memoized, unlike
import. So importing a file multiple times leads to multiple parsings
/ evaluations. It would be possible to construct the AST only once,
but that would require careful handling of variables/environments.
2014-05-26 14:26:29 +02:00
Shea Levy 908e9ce259 If a dynamic attribute name evaluates to null, remove it from the set 2014-03-10 10:14:50 +01:00
Eelco Dolstra 5ad263c26b Test some more primops 2014-02-26 19:08:44 +01:00
Shea Levy f9913f4422 Allow "bare" dynamic attrs
Now, in addition to a."${b}".c, you can write a.${b}.c (applicable
wherever dynamic attributes are valid).

Signed-off-by: Shea Levy <shea@shealevy.com>
2014-01-14 14:00:15 +01:00
Eelco Dolstra 7a61c88dbb Merge branch 'dynamic-attrs-no-sugar' of github.com:shlevy/nix 2014-01-06 15:46:18 +01:00
Eelco Dolstra 4252b5a645 Disable the tail call test
On i686-linux, GCC stubbornly refuses to do tail-call optimisation.
Don't know why.

http://hydra.nixos.org/build/7300170
2014-01-06 11:32:22 +01:00
Shea Levy 6f3a51809a Fold dynamic binds handling into addAttr
Since addAttr has to iterate through the AttrPath we pass it, it makes
more sense to just iterate through the AttrNames in addAttr instead. As
an added bonus, this allows attrsets where two dynamic attribute paths
have the same static leading part (see added test case for an example
that failed previously).

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 17:57:10 -05:00
Shea Levy 18fefacf7d Dynamic attrs
This adds new syntax for attribute names:

* attrs."${name}" => getAttr name attrs
* attrs ? "${name}" => isAttrs attrs && hasAttr attrs name
* attrs."${name}" or def => if attrs ? "${name}" then attrs."${name}" else def
* { "${name}" = value; } => listToAttrs [{ inherit name value; }]

Of course, it's a bit more complicated than that. The attribute chains
can be arbitrarily long and contain combinations of static and dynamic
parts (e.g. attrs."${foo}".bar."${baz}" or qux), which is relatively
straightforward for the getAttrs/hasAttrs cases but is more complex for
the listToAttrs case due to rules about duplicate attribute definitions.

For attribute sets with dynamic attribute names, duplicate static
attributes are detected at parse time while duplicate dynamic attributes
are detected when the attribute set is forced. So, for example, { a =
null; a.b = null; "${"c"}" = true; } will be a parse-time error, while
{ a = {}; "${"a"}".b = null; c = true; } will be an eval-time error
(technically that case could theoretically be detected at parse time,
but the general case would require full evaluation). Moreover, duplicate
dynamic attributes are not allowed even in cases where they would be
with static attributes ({ a.b.d = true; a.b.c = false; } is legal, but {
a."${"b"}".d = true; a."${"b"}".c = false; } is not). This restriction
might be relaxed in the future in cases where the static variant would
not be an error, but it is not obvious that that is desirable.

Finally, recursive attribute sets with dynamic attributes have the
static attributes in scope but not the dynamic ones. So rec { a = true;
"${"b"}" = a; } is equivalent to { a = true; b = true; } but rec {
"${"a"}" = true; b = a; } would be an error or use a from the
surrounding scope if it exists.

Note that the getAttr, getAttr or default, and hasAttr are all
implemented purely in the parser as syntactic sugar, while attribute
sets with dynamic attribute names required changes to the AST to be
implemented cleanly.

This is an alternative solution to and closes #167

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 20:59:49 +00:00
Shea Levy 136f2f7046 Add the ExprBuiltin Expr type to the AST
Certain desugaring schemes may require the parser to use some builtin
function to do some of the work (e.g. currently `throw` is used to
lazily cause an error if a `<>`-style path is not in the search path)
Unfortunately, these names are not reserved keywords, so an expression
that uses such a syntactic sugar will not see the expected behavior
(see tests/lang/eval-okay-redefine-builtin.nix for an example).

This adds the ExprBuiltin AST type, which when evaluated uses the value
from the rootmost variable scope (which of course is initialized
internally and can't shadow any of the builtins).

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 17:45:47 +00:00
Eelco Dolstra 77c13cdf56 Add a toJSON primop 2013-11-19 00:04:11 +01:00
Eelco Dolstra 285df765b9 Add a primop unsafeGetAttrPos to return the position of an attribute 2013-11-18 22:22:35 +01:00
Eelco Dolstra fc33fd86b7 Add a symbol __curPos that expands to the current source location
I.e. an attribute set { file = <string>; line = <int>; column = <int>; }.
2013-11-18 20:16:02 +01:00
Eelco Dolstra 2bcb384e95 Add a test to check that tail calls run in bounded stack space 2013-11-12 12:34:22 +01:00
Eelco Dolstra 5bc41d78ff Rename "attribute sets" to "sets"
We don't have any other kind of sets so calling them attribute sets is
unnecessarily verbose.
2013-10-24 16:41:04 +02:00
Eelco Dolstra 411a3461dc Add a test of the type primops 2013-10-24 02:51:28 +02:00
Eelco Dolstra 9d8a80375d Add a test for type correctness of antiquotes
Antiquotes should evaluate to strings or paths.  This is usually
checked, except in the case where the antiquote makes up the entire
string, as in "${expr}".  This is optimised to expr, which discards
the runtime type checks / coercions.
2013-10-17 00:51:07 +02:00
Eelco Dolstra b8571d68c4 Add a regression test for correct path antiquotation behavior
This broke in Nix 1.6.
2013-10-16 23:29:11 +02:00
Shea Levy afc6c1bad6 Simplify inherited attribute handling
This reduces the difference between inherited and non-inherited
attribute handling to the choice of which env to use (in recs and lets)
by setting the AttrDef::e to a new ExprVar in the parser rather than
carrying a separate AttrDef::v VarRef member.

As an added bonus, this allows inherited attributes that inherit from a
with to delay forcing evaluation of the with's attributes.

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-08-26 11:31:56 +02:00
Ivan Kozik 34bb806f74 Fix typos, especially those that end up in the Nix manual 2013-08-26 11:15:22 +02:00
Eelco Dolstra 8e74c0bfd1 Let the ordering operators also work on strings
E.g. ‘"foo" < "bar"’ now works.
2013-08-02 18:53:02 +02:00
Eelco Dolstra 3d77b28eac Add comparison operators ‘<’, ‘<=’, ‘>’ and ‘>=’ 2013-08-02 18:39:40 +02:00
Eelco Dolstra 47701677e8 Add integer ‘-’, ‘*’ and ‘/’ operators 2013-08-02 16:03:02 +00:00
Eelco Dolstra 5d147e125c Add a unary integer negation operator
This allows saying "-1" instead of "builtins.sub 0 1".
2013-08-02 15:43:31 +00:00
Eelco Dolstra 159e621d1a Overload the ‘+’ operator to support integer addition 2013-08-02 15:21:17 +00:00
Eelco Dolstra 7df4ef983e Test the delayed with a bit more 2013-07-31 13:12:35 +02:00
Shea Levy 20866a7031 Delay evaulation of with attrs until a variable lookup needs them
Evaluation of attribute sets is strict in the attribute names, which
means immediate evaluation of `with` attribute sets rules out some
potentially interesting use cases (e.g. where the attribute names of one
set depend in some way on another but we want to bring those names into
scope for some values in the second set).

The major example of this is overridable self-referential package sets
(e.g. all-packages.nix). With immediate `with` evaluation, the only
options for such sets are to either make them non-recursive and
explicitly use the name of the overridden set in non-overridden one
every time you want to reference another package, or make the set
recursive and use the `__overrides` hack. As shown in the test case that
comes with this commit, though, delayed `with` evaluation allows a nicer
third alternative.

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-07-31 11:48:39 +02:00
Eelco Dolstra 52172607cf Rename "hash" to "hashString" and handle SHA-1 2013-02-08 19:36:23 +01:00
Marc Weber 01a5ea9914 experimental/hash
adding primop function calculating hash of a string

Signed-off-by: Marc Weber <marco-oweber@gmx.de>
2013-02-08 19:26:34 +01:00
Eelco Dolstra 95c74eae26 Allow dashes in identifiers
In Nixpkgs, the attribute in all-packages.nix corresponding to a
package is usually equal to the package name.  However, this doesn't
work if the package contains a dash, which is fairly common.  The
convention is to replace the dash with an underscore (e.g. "dbus-lib"
becomes "dbus_glib"), but that's annoying.  So now dashes are valid in
variable / attribute names, allowing you to write:

  dbus-glib = callPackage ../development/libraries/dbus-glib { };

and

  buildInputs = [ dbus-glib ];

Since we don't have a negation or subtraction operation in Nix, this
is unambiguous.
2012-09-27 15:49:20 -04:00
Eelco Dolstra 126c7317bc * Add a test case for comparing derivations. 2012-01-19 22:10:24 +00:00
Eelco Dolstra 48cea0d01e * Refactoring: Get rid of a few subdirectories in corepkgs/, and some
other simplifications.
* Use <nix/...> to locate the corepkgs.  This allows them to be
  overriden through $NIX_PATH.
* Use bash's pipefail option in the NAR builder so that we don't need
  to create a temporary file.
2012-01-03 00:16:29 +00:00
Eelco Dolstra 3877619888 * Add some accidentally committed files. 2011-12-21 11:47:52 +00:00
Eelco Dolstra 07340b8be7 * Add the Nix corepkgs to the end of the search path. This makes it
possible for other Nix expressions to use corepkgs (mostly useful
  for the buildenv function).
2011-08-06 18:23:38 +00:00
Eelco Dolstra c7101dac0b * Allow redirections in search path entries. E.g. if you have a
directory

    /home/eelco/src/stdenv-updates

  that you want to use as the directory for import such as

    with (import <nixpkgs> { });

  then you can say

    $ nix-build -I nixpkgs=/home/eelco/src/stdenv-updates
2011-08-06 17:48:57 +00:00
Eelco Dolstra 1ecc97b6bd * Add a Nix expression search path feature. Paths between angle
brackets, e.g.

    import <nixpkgs/pkgs/lib>

  are resolved by looking them up relative to the elements listed in
  the search path.  This allows us to get rid of hacks like

    import "${builtins.getEnv "NIXPKGS_ALL"}/pkgs/lib"

  The search path can be specified through the ‘-I’ command-line flag
  and through the colon-separated ‘NIX_PATH’ environment variable,
  e.g.,

    $ nix-build -I /etc/nixos ...

  If a file is not found in the search path, an error message is
  lazily thrown.
2011-08-06 16:05:24 +00:00
Eelco Dolstra d5d4dcd4c9 * Allow attribute names to be strings. Based on the
allow-arbitrary-strinsg-in-names patch by Marc Weber.
2011-07-13 15:53:24 +00:00
Eelco Dolstra 0a623a10c7 * Allow a default value in attribute selection by writing
x.y.z or default

  (as originally proposed in
  https://mail.cs.uu.nl/pipermail/nix-dev/2009-September/002989.html).

  For instance, an expression like

    stdenv.lib.attrByPath ["features" "ckSched"] false args

  can now be written as

    args.features.ckSched or false
2011-07-13 12:19:57 +00:00
Eelco Dolstra 5580f3817c * Test case. 2011-07-06 10:58:53 +00:00
Eelco Dolstra 9db190eb31 * builtins.substring: if "start" is beyond the end of the string,
return the empty string.
2011-01-14 12:47:10 +00:00
Eelco Dolstra e0b7fb8f27 * Keep attribute sets in sorted order to speed up attribute lookups.
* Simplify the representation of attributes in the AST.
* Change the behaviour of listToAttrs() in case of duplicate names.
2010-10-24 19:52:33 +00:00
Eelco Dolstra 02934b1200 * Regression test for listToAttr's behaviour if an attribute name
occurs multiple times.
2010-10-23 22:55:30 +00:00
Eelco Dolstra cf7e645a48 * Regression test for __overrides. 2010-10-22 15:15:12 +00:00
Eelco Dolstra bd25ac2260 * Print attributes in sorted order. 2010-05-12 12:15:49 +00:00
Eelco Dolstra 81a4b4e49b * Implemented tryEval, the last missing primop in the fast-eval
branch.  Also added a test for tryEval.
2010-05-12 11:23:44 +00:00
Eelco Dolstra 83dfa89870 * Sync with the trunk. 2010-05-07 14:46:47 +00:00
Eelco Dolstra ebade9ff8b * Check for duplicate attribute names / function arguments. `make
check' now succeeds :-)
* An attribute set such as `{ foo = { enable = true; };
  foo.port = 23; }' now parses.  It was previously rejected, but I'm
  too lazy to implement the check.  (The only reason to reject it is
  that the reverse, `{ foo.port = 23; foo = { enable = true; }; }', is
  rejected, which is kind of ugly.)
2010-04-22 11:02:24 +00:00
Eelco Dolstra 7148df7971 * Update the expected test output (no longer an ATerm). 2010-04-21 16:22:03 +00:00
Eelco Dolstra cae4efdca3 * Because --parse-only no longer produces an ATerm, don't check the
output.  Whether it parses at all should be enough.
2010-04-21 16:02:12 +00:00
Eelco Dolstra 5187678913 2010-03-31 15:14:23 +00:00
Eelco Dolstra f061086a93 * Fix the broken test for listToAttrs. 2010-03-31 13:35:29 +00:00
Ludovic Courtès 09381cccff Make source location info in the XML output optional.
* src/libexpr/expr-to-xml.cc (nix::showAttrs): Add `location'
  parameter.  Provide location XML attributes when it's true.  Update
  callers.
  (nix::printTermAsXML): Likewise.

* src/libexpr/expr-to-xml.hh (nix::printTermAsXML): Update prototype;
  have `location' default to `false'.

* src/nix-instantiate/nix-instantiate.cc (printResult, processExpr): Add
  `location' parameter; update callers.
  (run): Add support for `--no-location'.

* src/nix-instantiate/help.txt: Update accordingly.

* tests/lang.sh: Invoke `nix-instantiate' with `--no-location' for the
  XML tests.

* tests/lang/eval-okay-toxml.exp, tests/lang/eval-okay-to-xml.nix: New
  files.
2010-03-31 12:38:31 +00:00
Eelco Dolstra 8a10360c91 * Simplify @-patterns: only {attrs}@name' or name@{attrs}' are now
allowed.  So `name1@name2', `{attrs1}@{attrs2}' and so on are now no
  longer legal.  This is no big loss because they were not useful
  anyway.

  This also changes the output of builtins.toXML for @-patterns
  slightly.
2010-03-25 12:19:41 +00:00
Eelco Dolstra 71be50cc25 * Doh. 2010-03-23 14:51:32 +00:00
Eelco Dolstra 3bfd3a4e95 * Test "with as; with bs;" since nobody knows what its semantics is. 2010-03-23 14:26:27 +00:00
Eelco Dolstra 0dbd4638e0 * Two primops: builtins.intersectAttrs and builtins.functionArgs.
intersectAttrs returns the (right-biased) intersection between two
  attribute sets, e.g. every attribute from the second set that also
  exists in the first.  functionArgs returns the set of attributes
  expected by a function.

  The main goal of these is to allow the elimination of most of
  all-packages.nix.  Most package instantiations in all-packages.nix
  have this form:

    foo = import ./foo.nix {
      inherit a b c;
    };

  With intersectAttrs and functionArgs, this can be written as:

    foo = callPackage (import ./foo.nix) { };

  where

   callPackage = f: args:
     f ((builtins.intersectAttrs (builtins.functionArgs f) pkgs) // args);

  I.e., foo.nix is called with all attributes from "pkgs" that it
  actually needs (e.g., pkgs.a, pkgs.b and pkgs.c).  (callPackage can
  do any other generic package-level stuff we might want, such as
  applying makeOverridable.)  Of course, the automatically supplied
  arguments can be overriden if needed, e.g.

    foo = callPackage (import ./foo.nix) {
      c = c_version_2;
    };

  but for the vast majority of packages, this won't be needed.

  The advantages are to reduce the amount of typing needed to add a
  dependency (from three sites to two), and to reduce the number of
  trivial commits to all-packages.nix.  For the former, there have
  been two previous attempts:

    - Use "args: with args;" in the package's function definition.
      This however obscures the actual expected arguments of a
      function, which is very bad.

    - Use "{ arg1, arg2, ... }:" in the package's function definition
      (i.e. use the ellipis "..." to allow arbitrary additional
      arguments), and then call the function with all of "pkgs" as an
      argument.  But this inhibits error detection if you call it with
      an misspelled (or obsolete) argument.
2009-09-15 13:01:46 +00:00
Eelco Dolstra a64bbe049e * Change the scoping of "inherit (e) ..." in recs so that the
attributes of the rec are in scope of `e'.  This is useful in
  expressions such as

    rec {
      lib = import ./lib;
      inherit (lib) concatStrings;
    }

  It does change the semantics of expressions such as

    let x = {y = 1;}; in rec { x = {y = 2;}; inherit (x) y; }.y

  This now returns 2 instead of 1.  However, no code in Nixpkgs or
  NixOS seems to rely on the old behaviour.
2009-05-15 13:46:13 +00:00
Eelco Dolstra d407d572fd * Some syntactic sugar for attribute sets: allow {x.y.z = ...;} as a
shorthand for {x = {y = {z = ...;};};}.  This is especially useful
  for NixOS configuration files, e.g.

    {
      services = {
        sshd = {
          enable = true;
          port = 2022;
        };
      };
    }

  can now be written as

    {
      services.sshd.enable = true;
      services.sshd.port = 2022;
    }

  However, it is currently not permitted to write
  
    {
      services.sshd = {enable = true;};
      services.sshd.port = 2022;
    }

  as this is considered a duplicate definition of `services.sshd'.
2009-05-15 12:35:23 +00:00
Eelco Dolstra 9279174dde * Added an experimental feature suggested by Andres: ellipses ("...")
in attribute set pattern matches.  This allows defining a function
  that takes *at least* the listed attributes, while ignoring
  additional attributes.  For instance,

    {stdenv, fetchurl, fuse, ...}:
    
    stdenv.mkDerivation {
      ...
    };
    
  defines a function that requires an attribute set that contains the 
  specified attributes but ignores others.  The main advantage is that
  we can then write in all-packages.nix

    aefs = import ../bla/aefs pkgs;

  instead of

    aefs = import ../bla/aefs {
      inherit stdenv fetchurl fuse;
    };

  This saves a lot of typing (not to mention not having to update
  all-packages.nix with purely mechanical changes).  It saves as much
  typing as the "args: with args;" style, but has the advantage that
  the function arguments are properly declared (not implicit in what
  the body of the "with" uses).
2008-08-14 14:00:44 +00:00
Eelco Dolstra 1b962fc720 * @-patterns as in Haskell. For instance, in a function definition
f = args @ {x, y, z}: ...;

  `args' refers to the argument as a whole, which is further
  pattern-matched against the attribute set pattern {x, y, z}.
2008-08-14 12:53:29 +00:00
Eelco Dolstra efe4b690ae * Refactoring: combine functions that take an attribute set and
functions that take a single argument (plain lambdas) into one AST
  node (Function) that contains a Pattern node describing the
  arguments.  Current patterns are single lazy arguments (VarPat) and
  matching against an attribute set (AttrsPat).

  This refactoring allows other kinds of patterns to be added easily,
  such as Haskell-style @-patterns, or list pattern matching.
2008-08-14 10:04:22 +00:00
Eelco Dolstra 5664b6d7ba * Removed the "valid values" feature. Nobody uses it anyway. 2008-08-11 13:36:40 +00:00
Eelco Dolstra 7cd88b1dec * Generalised the dependencyClosure primop to builtins.genericClosure,
which is hopefully more useful.
* New primops: length, mul, div.
2008-07-11 13:29:04 +00:00
Eelco Dolstra d567baabbd * Export the nix-env derivation name parsing and version comparison
logic through the `parseDrvName' and `compareVersions' primops.
  This will allow expressions to easily check whether some dependency
  is a specific needed version or falls in some version range.  See
  tests/lang/eval-okay-versions.nix for examples.
2008-07-01 10:10:32 +00:00
Eelco Dolstra 4066f450c2 * Doh. 2008-02-05 13:35:49 +00:00
Eelco Dolstra e7bdde981f * Regression test. 2008-02-05 13:25:18 +00:00
Eelco Dolstra 7d0f6aed59 * New primop `unsafeDiscardStringContext' to get rid of string
contexts.  Needed to prevent unnecessary dependencies when building
  the NixOS manual.
2008-01-04 14:22:49 +00:00