Commit graph

827 commits

Author SHA1 Message Date
Christian Theune 494fc5acbb Try a simplified version of float lexing that didn't work.
The last one I tried was botchered anyway ...
2016-01-05 00:53:22 +01:00
Christian Theune 14ebde5289 First hit at providing support for floats in the language. 2016-01-05 00:40:40 +01:00
Eelco Dolstra a9faa7bbce showId: Handle empty attribute names
We should probably disallow these, but until then, we shouldn't barf
with an assertion failure.

Fixes #738.
2015-12-17 15:15:28 +01:00
Shea Levy f327970129 Merge branch 'auto-call-functor'
autoCallFunction now auto-calls functors
2015-11-25 11:57:31 -05:00
Shea Levy 9533532ce2 autoCallFunction: Auto-call functors 2015-11-25 11:56:14 -05:00
Eelco Dolstra cad40adce5 Merge pull request #704 from ysangkok/freebsd-support
FreeBSD support with knowledge about Linux emulation
2015-11-24 19:24:21 +01:00
Eelco Dolstra 5c28943e8f int2String() -> std::to_string() 2015-10-29 13:26:55 +01:00
Eelco Dolstra 51cf4455b2 isFunctor: Simplify 2015-10-08 13:22:11 +02:00
Mathnerd314 8a87521636 forceFunction: allow functors as well 2015-10-08 13:19:44 +02:00
Manuel Jacob 12c1776df9 Don't try to link libdl on FreeBSD.
There is no libdl on FreeBSD.  Instead the symbols are included in libc.
2015-10-06 22:28:30 +02:00
Eelco Dolstra 4ba6bc184c Shut up clang warnings 2015-09-18 01:22:35 +02:00
Iwan Aucamp 3db950aab7 Removed unnecessary included 2015-08-03 11:48:34 +02:00
Eelco Dolstra 2bac04c5ff Fix stack consumption 2015-07-31 20:28:25 +02:00
Iwan Aucamp 75837651f1 Output line number on infinite recursion 2015-07-31 20:26:44 +02:00
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 cb4320c1a0 Cleanup 2015-07-23 23:14:07 +02:00
Eelco Dolstra c8bb2371eb Optimize empty sets
This reduces the number of Bindings allocations by about 10%.
2015-07-23 23:11:08 +02:00
Eelco Dolstra 19eddecc0f Merge branch 'attr-set-hh' of https://github.com/nbp/nix
Conflicts:
	src/libexpr/eval.cc
2015-07-23 22:16:01 +02:00
Eelco Dolstra b83801f8b3 Optimize small lists
The value pointers of lists with 1 or 2 elements are now stored in the
list value itself. In particular, this makes the "concatMap (x: if
cond then [(f x)] else [])" idiom cheaper.
2015-07-23 22:05:09 +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
Shea Levy 39e27a04b8 Importing derivations: Add name attribute to make a valid drv 2015-07-23 17:04:07 +02:00
Shea Levy 1ed55234d9 Allow derivations-as-srcs in the context of builtins.toFile files 2015-07-23 17:03:47 +02:00
Eelco Dolstra 61af14a921 Add foldl' primop 2015-07-23 17:03:02 +02:00
Eelco Dolstra 0a2bee307b Make <nix/fetchurl.nix> a builtin builder
This ensures that 1) the derivation doesn't change when Nix changes;
2) the derivation closure doesn't contain Nix and its dependencies; 3)
we don't have to rely on ugly chroot hacks.
2015-07-20 04:38:46 +02:00
Eelco Dolstra 6bd2c7bb38 OCD: foreach -> C++11 ranged for 2015-07-17 20:13:56 +02:00
Eelco Dolstra f39979c6d3 Make printValue() interruptible
Fixes #572.
2015-07-17 11:33:39 +02:00
Nicolas B. Pierron db21cfa688 Move attribute set data structures into their own header file.
This modification moves Attr and Bindings structures into their own header
file which is dedicated to the attribute set representation. The goal of to
isolate pieces of code which are related to the attribute set
representation. Thus future modifications of the attribute set
representation will only have to modify these files, and not every other
file across the evaluator.
2015-07-14 19:23:17 +02:00
Guillaume Maudoux 467977f203 Fix the parsing of "$"'s in strings. 2015-07-03 14:09:58 +02:00
Guillaume Maudoux 65e4dcd69b Fix the hack that resets the scanner state. 2015-07-03 13:53:36 +02:00
Eelco Dolstra 65f17cd330 Support URLs in $NIX_PATH
This didn't work (despite claims in the manual), because the colon in
"http://" was parsed as a element separator. So handle "://"
specially.
2015-06-17 16:20:11 +02:00
Eelco Dolstra bc51175dc0 Add tarball tests 2015-06-01 16:18:23 +02:00
Eelco Dolstra da196ec68f Document tarball downloading 2015-06-01 15:14:44 +02:00
Eelco Dolstra c1323b53e3 Fix fetchurl/fetchTarball 2015-06-01 15:08:09 +02:00
Eelco Dolstra 1c88e100e7 readFile: Check against nul bytes 2015-06-01 15:07:42 +02:00
Eelco Dolstra 920f5fd4dd Fix import-from-derivation in restricted eval mode
This relaxes restricted mode to allow access to anything in the
store. In the future, it would be better to allow access to only paths
that have been constructed in the current evaluation (so a hard-coded
/nix/store/blabla in a Nix expression would still be
rejected). However, note that reading /nix/store itself is still
rejected, so you can't use this so get access to things you don't know
about.
2015-05-22 12:18:23 +02:00
Eelco Dolstra 6519f06f39 nix-env/nix-instantiate/nix-build: Support URIs
For instance, you can install Firefox from a specific Nixpkgs revision
like this:

  $ nix-env -f 63def04891.tar.gz -iA firefox

Or build a package from the latest nixpkgs-unstable channel:

  $ nix-build https://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz -A hello
2015-05-06 14:54:31 +02:00
Eelco Dolstra 9451ef3731 Allow URLs in the Nix search path
E.g. to install "hello" from the latest Nixpkgs:

  $ nix-build '<nixpkgs>' -A hello -I nixpkgs=https://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz

Or to install a specific version of NixOS:

  $ nixos-rebuild switch -I nixpkgs=63def04891.tar.gz
2015-05-05 17:09:42 +02:00
Eelco Dolstra 35d30d67eb Make downloads interruptable 2015-05-05 14:39:48 +02:00
Eelco Dolstra 035aeb9547 Fix using restricted mode with chroots 2015-04-16 18:46:17 +02:00
Eelco Dolstra 4ed2187377 Use cached result if there is a network error 2015-04-09 12:49:13 +02:00
Eelco Dolstra 1fc905ad4c Move curl stuff into a separate file 2015-04-09 12:12:50 +02:00
Eelco Dolstra c1f04fae35 Implement a TTL on cached fetchurl/fetchTarball results
This is because we don't want to do HTTP requests on every evaluation,
even though we can prevent a full redownload via the cached ETag. The
default is one hour.
2015-04-09 11:55:36 +02:00
Eelco Dolstra 60340ce3e2 Implement caching of fetchurl/fetchTarball results
ETags are used to prevent redownloading unchanged files.
2015-04-09 11:42:04 +02:00
Eelco Dolstra 000b5a000f Add fetchTarball builtin
This function downloads and unpacks the given URL at evaluation
time. This is primarily intended to make it easier to deal with Nix
expressions that have external dependencies. For instance, to fetch
Nixpkgs 14.12:

  with import (fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz) {};

Or to fetch a specific revision:

  with import (fetchTarball 2766a4b44e.tar.gz) {};

This patch also adds a ‘fetchurl’ builtin that downloads but doesn't
unpack its argument. Not sure if it's useful though.
2015-03-25 17:29:09 +01:00
Eelco Dolstra 7ea6ecf855 addToStore(): Take explicit name argument 2015-03-25 17:06:12 +01:00
Eelco Dolstra 6f0c6e20e0 Don't rely on __noChroot for corepkgs
This doesn't work anymore if the "strict" chroot mode is
enabled. Instead, add Nix's store path as a dependency. This ensures
that its closure is present in the chroot.
2015-03-24 11:15:45 +01:00
Eelco Dolstra b005e63ccf Disable scanning for interior pointers
This may remove the "Repeated allocation of very large block"
warnings.
2015-03-19 20:10:08 +01:00
Eelco Dolstra 726f7f7fc9 Fix Boehm API violation
We were calling GC_INIT() after doing an allocation (in the baseEnv
construction), which is not allowed.
2015-03-19 20:02:37 +01:00
Eelco Dolstra da6b704b19 Check return values from malloc/strdup 2015-03-19 14:11:35 +01:00
Eelco Dolstra fa47279440 Print some Boehm GC stats 2015-03-18 16:24:54 +01:00
Eelco Dolstra 7a84143910 valueSize(): Take into account list/bindings/env size 2015-03-18 14:41:28 +01:00
Daniel Hahler e659978ced Fix typos: s/the the/the/ 2015-03-06 16:43:22 +01:00
Eelco Dolstra 17c71334e1 forceValueDeep: Add to error prefix 2015-03-06 15:10:12 +01:00
Eelco Dolstra 5badc8f975 Improve error message 2015-03-06 14:24:08 +01:00
Eelco Dolstra 15d2d3c34e Add restricted evaluation mode
If ‘--option restrict-eval true’ is given, the evaluator will throw an
exception if an attempt is made to access any file outside of the Nix
search path. This is primarily intended for Hydra, where we don't want
people doing ‘builtins.readFile ~/.ssh/id_dsa’ or stuff like that.
2015-02-23 15:54:31 +01:00
Eelco Dolstra c33244d7c1 Merge branch 'tilde-paths' of https://github.com/shlevy/nix 2015-02-19 14:55:06 +01:00
Shea Levy c4653afbcd tilde paths: The rest of the string has to start with a slash anyway 2015-02-19 08:52:13 -05:00
Shea Levy e3e38a048e tilde paths: construct the entire path at parse time 2015-02-19 08:51:21 -05:00
Shea Levy 4b7c9f834c tilde paths: get HOME at parse time 2015-02-19 08:49:10 -05:00
Eelco Dolstra 9bedd9b09b Remove obsolete reference to ~ operator 2015-02-19 14:41:22 +01:00
Shea Levy 4646e94610 ExprConcatStrings: canonicalize concatenated paths 2015-02-19 08:39:25 -05:00
Shea Levy e0953d53de Allow the leading component of a path to be a ~ 2015-02-19 08:05:16 -05:00
Eelco Dolstra 2be7f79fd4 Remove tab 2015-02-05 17:21:30 +01:00
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 c2a8b5c42d Fix assertion failure in nix-env
$ nix-env -f ~/Dev/nixops/ -iA foo
  nix-env: src/libexpr/eval.hh:57: void nix::Bindings::push_back(const nix::Attr&): Assertion `size_ < capacity' failed.
  Aborted
2015-01-15 12:15:22 +01:00
Eelco Dolstra 2a3b1df423 Fix builtins.readDir on XFS
The DT_UNKNOWN fallback code was getting the type of the wrong path,
causing readDir to report "directory" as the type of every file.

Reported by deepfire on IRC.
2015-01-09 14:56:25 +01:00
Eelco Dolstra 153a943de7 Show position info for failing <...> lookups 2015-01-07 13:43:55 +01:00
Eelco Dolstra 6fec43ccb3 Remove quotes around filenames in position info 2015-01-07 12:08:10 +01:00
Eelco Dolstra 4e0607369e Pedantry 2014-12-14 01:51:14 +01:00
Eelco Dolstra 8aedaf111e Remove canary stuff 2014-12-12 10:59:50 +01:00
Shea Levy 50c3352811 builtins.readFile: realise context associated with the path 2014-12-10 12:26:53 +01:00
Shea Levy 608110804c Make all ExternalValueBase functions const 2014-12-02 10:27:10 -05:00
Shea Levy 320659b0cd Allow external code using libnixexpr to add types
Code that links to libnixexpr (e.g. plugins loaded with importNative, or
nix-exec) may want to provide custom value types and operations on
values of those types. For example, nix-exec is currently using sets
where a custom IO value type would be more appropriate. This commit
provides a generic hook for such types in the form of tExternal and the
ExternalBase virtual class, which contains all functions necessary for
libnixexpr's type-polymorphic functions (e.g. `showType`) to be
implemented.
2014-12-02 10:27:04 -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
Eelco Dolstra 4e340a983f forceString(): Accept pos argument 2014-11-25 10:23:36 +01:00
Shea Levy b0c5c2ac34 import derivation: cleanup
Before this there was a bug where a `find` was being called on a
not-yet-sorted set. The code was just a mess before anyway, so I cleaned
it up while fixing it.
2014-11-20 22:48:12 -05:00
Shea Levy 2719627bbe realiseContext: Handle all context types
Avoids an assertion
2014-11-15 21:43:51 -05:00
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
Eelco Dolstra 3a9b4a1467 Fix more warnings 2014-10-31 08:49:15 +01:00
Shea Levy 6062b12160 Fix build on gcc < 4.7 2014-10-20 12:15:50 -04:00
Eelco Dolstra ecc2c8f464 Improve printing of ASTs 2014-10-20 09:13:21 +02:00
Shea Levy 0ee1ca628a baseNameOf: Don't copy paths to the store first 2014-10-18 20:28:28 -04:00
Shea Levy d16e3c7f09 Export realiseContext in libnixexpr
Useful for importNative plugins
2014-10-17 22:15:09 -04:00
Eelco Dolstra 6bb4c0b712 mkList: Scrub better
Clearing v.app.right was not enough, because the length field of a
list only takes 32 bits, so the most significant 32 bits of v.app.left
(a.k.a. v.thunk.env) would remain. This could cause Boehm GC to
interpret it as a valid pointer.

This change reduces maximum RSS for evaluating the ‘tested’ job in
nixos/release-small.nix from 1.33 GiB to 0.80 GiB, and runtime by
about 8%.
2014-10-09 13:08:53 +02:00
Eelco Dolstra 986fbd6fab Typo 2014-10-09 11:34:48 +02:00
Eelco Dolstra b6809608cc Get rid of some unnecessary ExprConcatStrings nodes in dynamic attrs
This gives a ~18% speedup in NixOS evaluation (after converting
most calls to hasAttr/getAttr to dynamic attrs).
2014-10-05 01:04:58 +02:00
Eelco Dolstra 1418806969 Show total allocations 2014-10-05 00:39:28 +02:00
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
Eelco Dolstra 58d8a213b0 Tweak 2014-10-04 11:27:23 +02:00
Eelco Dolstra 3f8576a6ab Remove some duplicate code 2014-10-03 22:37:51 +02:00
Shea Levy c08c802bf3 Add readDir primop 2014-10-03 22:32:11 +02:00
Eelco Dolstra 3b5fa8d50c Don't recompile the same regex over and over 2014-10-03 21:29:40 +02:00
Eelco Dolstra 104e55bb7f nix-env: Add regular expression support in selectors
So you can now do things like:

  $ nix-env -qa '.*zip.*'
  $ nix-env -qa '.*(firefox|chromium).*'
2014-10-03 21:29:40 +02:00
Eelco Dolstra a17c23426e printValue(): Don't print <CYCLE> for repeated values 2014-10-01 15:54:40 +02:00
Eelco Dolstra d61853430a Support control characters in JSON output 2014-09-30 00:41:18 +02:00
Eelco Dolstra 0ed1b924be Bindings: Remove copy constructor 2014-09-24 15:29:05 +02:00
Eelco Dolstra ebb1dbb3e1 Add missing static 2014-09-23 15:08:27 +02:00
Eelco Dolstra 53b044c2f6 Don't evaluate inside a "throw"
Workaround for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41174. This caused
hydra-eval-jobs to ignore SIGINT.
2014-09-22 19:18:05 +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 831fc8ea21 Make forceValueDeep work on values with cycles 2014-09-22 16:05:00 +02:00
Eelco Dolstra 1e0a799bef Rename strictForceValue -> forceValueDeep 2014-09-22 16:05:00 +02:00
Eelco Dolstra 022618c794 Handle cycles when printing a value
So this no longer crashes with a stack overflow:

  nix-instantiate -E --eval 'let as = { x = as; }; in as'

Instead it prints:

  { x = { x = <CYCLE>; }; }
2014-09-22 16:05:00 +02:00
Eelco Dolstra a54c263402 Add ‘seq’ primop 2014-09-22 16:05:00 +02:00
Eelco Dolstra eff120d1b9 Add a function ‘valueSize’
It returns the size of value, including all other values and
environments reachable from it. It is intended for debugging memory
consumption issues.
2014-09-22 16:05:00 +02:00
Eelco Dolstra 2d6cd8aafd attrNames: Don't allocate duplicates of the symbols 2014-09-19 18:11:46 +02:00
Eelco Dolstra ea525a261f Fix off-by-one 2014-09-19 18:08:14 +02:00
Eelco Dolstra 93e4f01ee3 Inline Bindings::find() 2014-09-19 16:56:13 +02:00
Eelco Dolstra 5b58991a71 Store Attrs inside Bindings
This prevents a double allocation per attribute set.
2014-09-19 16:49:41 +02:00
Eelco Dolstra d4a71ec3bf Update spec file
http://hydra.nixos.org/build/14344391
2014-09-18 15:42:01 +02:00
Eelco Dolstra 8be9990cdb Install some pkgconfig files 2014-09-18 12:00:40 +02:00
Eelco Dolstra 6e5b02bee4 Add some instrumentation for debugging GC leaks 2014-09-17 15:19:07 +02:00
Eelco Dolstra 9d65287b91 Fix dependency ordering 2014-09-04 20:02:08 +02:00
Eelco Dolstra 9472b4157d Fix boost::too_many_args error
Fixes #333.
2014-09-02 22:53:01 +02:00
Eelco Dolstra fefd3650d4 Fix a segfault in ‘nix-env -qa’
This was triggered by 47e185847e, which
turned globals.state into a pointer.
2014-08-21 00:05:17 +02:00
Eelco Dolstra 11849a320e Use proper quotes everywhere 2014-08-20 18:03:48 +02:00
Eelco Dolstra 373fad75e1 Add some color 2014-08-20 16:50:17 +02:00
Eelco Dolstra 47e185847e Refactor option handling 2014-08-13 03:50:44 +02:00
Eelco Dolstra 5bed74d1b0 Fix warning about non-existant -I directories 2014-08-13 02:57:59 +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 62ad3dfc43 Remove some obsolete files 2014-07-23 23:56:58 +02:00
Eelco Dolstra 0e5d0c1543 Fix compilation error on some versions of GCC
src/libexpr/primops.cc:42:8: error: looser throw specifier for 'virtual nix::InvalidPathError::~InvalidPathError()'
src/libexpr/nixexpr.hh:12:1: error:   overriding 'virtual nix::EvalError::~EvalError() noexcept (true)'

http://hydra.nixos.org/build/12385750
2014-07-09 12:14:40 +02:00
Eelco Dolstra beaf3e90af Add builtin function ‘fromJSON’
Fixes #294.
2014-07-04 13:34:15 +02:00
Shea Levy d62f46e500 Only add the importNative primop if the allow-arbitrary-code-during-evaluation option is true (default false) 2014-06-24 10:50:03 -04:00
Shea Levy 5cd022d6c0 Add importNative primop
This can be used to import a dynamic shared object and return an
arbitrary value, including new primops. This can be used both to test
new primops without having to recompile nix every time, and to build
specialized primops that probably don't belong upstream (e.g. a function
that calls out to gpg to decrypt a nixops secret as-needed).

The imported function should initialize the Value & as needed. A single
import can define multiple values by creating an attrset or list, of
course.

An example initialization function might look like:

extern "C" void initialize(nix::EvalState & state, nix::Value & v)
{
    v.type = nix::tPrimOp;
    v.primOp = NEW nix::PrimOp(myFun, 1, state.symbols.create("myFun"));
}

Then `builtins.importNative ./example.so "initialize"` will evaluate to
the primop defined in the myFun function.
2014-06-17 12:08:01 -04:00
Eelco Dolstra 0960d674d4 Drop ImportError and FindError
We're not catching these anywhere.
2014-06-12 13:00:54 +02:00
Shea Levy 718f20da6d findFile: Realise the context of the path attributes 2014-06-12 12:57:14 +02:00
Shea Levy a8fb575c98 Share code between scopedImport and import
In addition to reducing duplication, this fixes both import from
derivation and import of derivation for scopedImport
2014-06-12 12:52:39 +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 becc2b0167 Sort nixPath attributes 2014-05-29 19:02:14 +02:00
Eelco Dolstra 54a34119f3 Use std::unordered_set 2014-05-26 17:53:17 +02:00
Eelco Dolstra d8c061e044 Remove ExprBuiltin
It's slower than ExprVar since it doesn't compute a static
displacement. Since we're not using the throw primop in the
implementation of <...> anymore, it's also not really needed.
2014-05-26 17:14:28 +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
Eelco Dolstra f0fdbd0897 Shut up some signedness warnings 2014-05-26 12:34:15 +02:00
Shea Levy eac5841970 Provide a more useful error message when a dynamic attr lookup fails 2014-05-15 17:56:24 +02:00
Eelco Dolstra dfa2f77d2e If a .drv cannot be parsed, show its path
Otherwise you just get ‘expected string `Derive(['’ which isn't very helpful.
2014-04-08 19:24:29 +02:00
Eelco Dolstra 8e5fbf4d73 Show position info in attribute selection errors 2014-04-04 22:52:14 +02:00
Eelco Dolstra 4c5faad994 Show position info in Boolean operations 2014-04-04 22:43:52 +02:00
Eelco Dolstra bd9b1d97b4 Show position info in string concatenation / addition errors 2014-04-04 22:19:33 +02:00
Eelco Dolstra a5fe730940 forceString: Show position info 2014-04-04 21:14:11 +02:00
Eelco Dolstra 27b44b8cf7 forceAttrs: Show position info 2014-04-04 19:11:40 +02:00
Eelco Dolstra 96b695ccab forceList: Show position info 2014-04-04 19:05:36 +02:00
Eelco Dolstra b62d36963c forceInt: Show position info 2014-04-04 18:59:29 +02:00
Eelco Dolstra c28de6d96e Pass position information to primop calls
For example:

  error: `tail' called on an empty list, at
    /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/ex-2/default.nix:13:7
2014-04-04 18:59:29 +02:00