Commit graph

171 commits

Author SHA1 Message Date
Eelco Dolstra
ab35cbd675 StaticEnv: Use std::vector instead of std::map 2021-11-04 15:03:34 +01:00
Ben Burdette
2ee1fa4afd add nullable Expr argument 2021-10-11 14:42:29 -06:00
Andreas Rammhold
cae41eebff libexpr: remove matchAttrs boolean from ExprLambda
The boolean is only used to determine if the formals are set to a
non-null pointer in all our cases. We can get rid of that allocation and
instead just compare the pointer value with NULL. Saving up to
sizeof(bool) + platform specific alignment per ExprLambda instace.
Probably not a lot of memory but perhaps a few kilobyte with nixpkgs?

This also gets rid of a potential issue with dereferencing formals based on
the value of the boolean that didn't have to be aligned with the formals
pointer but was in all our cases.
2021-10-06 17:24:06 +02:00
Ben Burdette
aad27143c6 storing staticenv bindings 2021-10-02 13:47:36 -06:00
Geoff Reedy
9d67332e4b Better eval error locations for interpolation and +
Previously, type or coercion errors for string interpolation, path
interpolation, and plus expressions were always reported at the
beginning of the outer expression. This leads to confusing evaluation
error messages making it hard to accurately diagnose and then fix the
error.

For example, errors were reported as follows.

```
cannot coerce an integer to a string
1| let foo = 7; in "bar" + foo
 |                 ^

cannot add a string to an integer
1| let foo = "bar"; in 4 + foo
 |                     ^

cannot coerce an integer to a string
1| let foo = 7; in "x${foo}"
 |                  ^
```

This commit changes the ExprConcatStrings expression vector to store a
sequence of expressions *and* their expansion locations so that error
locations can be reported accurately. For interpolation, the error is
reported at the beginning of the entire `${foo}`, not at the beginning
of `foo` because I thought this was slightly clearer. The previous
errors are now reported as:

```
cannot coerce an integer to a string
1| let foo = 7; in "bar" + foo
 |                         ^

cannot add a string to an integer
1| let foo = "bar"; in 4 + foo
 |                         ^

cannot coerce an integer to a string
1| let foo = 7; in "x${foo}"
 |                   ^
```

The error is reported at this kind of precise location even for
multi-line indented strings.

This probably helps with at least some of the cases mentioned in #561
2021-09-22 20:57:34 -06:00
Ben Burdette
cd8c232b55 add cout debugging 2021-09-15 16:16:53 -06:00
Ben Burdette
21071bfdeb shared_ptr for StaticEnv 2021-09-14 10:49:22 -06:00
Maximilian Bosch
7c76964daa
libexpr: misc improvements for proper error position
When working on some more complex Nix code, there are sometimes rather
unhelpful or misleading error messages, especially if coerce-errors are
thrown.

This patch is a first steps towards improving that. I'm happy to file
more changes after that, but I'd like to gather some feedback first.

To summarize, this patch does the following things:

* Attrsets (a.k.a. `Bindings` in `libexpr`) now have a `Pos`. This is
  helpful e.g. to identify which attribute-set in `listToAttrs` is
  invalid.

* The `Value`-struct has a new method named `determinePos` which tries
  to guess the position of a value and falls back to a default if that's
  not possible.

  This can be used to provide better messages if a coercion fails.

* The new `determinePos`-API is used by `builtins.concatMap` now. With
  that change, Nix shows the exact position in the error where a wrong
  value was returned by the lambda.

  To make sure it's still obvious that `concatMap` is the problem,
  another stack-frame was added.

* The changes described above can be added to every other `primop`, but
  first I'd like to get some feedback about the overall approach.
2021-04-13 23:12:38 +02:00
regnat
e2f3b2eb42 Make missing auto-call arguments throw an eval error
The PR #4240 changed messag of the error that was thrown when an auto-called
function was missing an argument.
However this change also changed the type of the error, from `EvalError`
to a new `MissingArgumentError`. This broke hydra which was relying on
an `EvalError` being thrown.

Make `MissingArgumentError` a subclass of `EvalError` to un-break hydra.
2021-02-22 16:13:09 +01:00
Eelco Dolstra
8d4268d190 Improve error formatting
Changes:

* The divider lines are gone. These were in practice a bit confusing,
  in particular with --show-trace or --keep-going, since then there
  were multiple lines, suggesting a start/end which wasn't the case.

* Instead, multi-line error messages are now indented to align with
  the prefix (e.g. "error: ").

* The 'description' field is gone since we weren't really using it.

* 'hint' is renamed to 'msg' since it really wasn't a hint.

* The error is now printed *before* the location info.

* The 'name' field is no longer printed since most of the time it
  wasn't very useful since it was just the name of the exception (like
  EvalError). Ideally in the future this would be a unique, easily
  googleable error ID (like rustc).

* "trace:" is now just "…". This assumes error contexts start with
  something like "while doing X".

Example before:

  error: --- AssertionError ---------------------------------------------------------------------------------------- nix
  at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix

       6|
       7|   x = assert false; 1;
        |       ^
       8|

  assertion 'false' failed
  ----------------------------------------------------- show-trace -----------------------------------------------------
  trace: while evaluating the attribute 'x' of the derivation 'hello-2.10'
  at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix

     191|         // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) {
     192|           name = "${attrs.pname}-${attrs.version}";
        |           ^
     193|         } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {

Example after:

  error: assertion 'false' failed

         at: (7:7) in file: /home/eelco/Dev/nixpkgs/pkgs/applications/misc/hello/default.nix

              6|
              7|   x = assert false; 1;
               |       ^
              8|

         … while evaluating the attribute 'x' of the derivation 'hello-2.10'

         at: (192:11) in file: /home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/make-derivation.nix

            191|         // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) {
            192|           name = "${attrs.pname}-${attrs.version}";
               |           ^
            193|         } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {
2021-01-21 11:02:09 +01:00
Domen Kožar
00f99fdfe6
Merge pull request #4240 from bburdette/2259-error-message
2259 error message - "auto-call" error
2021-01-15 18:26:21 +00:00
Silvan Mosberger
b70d22baca
Replace Value type setters with mk* functions
Move clearValue inside Value

mkInt instead of setInt

mkBool instead of setBool

mkString instead of setString

mkPath instead of setPath

mkNull instead of setNull

mkAttrs instead of setAttrs

mkList instead of setList*

mkThunk instead of setThunk

mkApp instead of setApp

mkLambda instead of setLambda

mkBlackhole instead of setBlackhole

mkPrimOp instead of setPrimOp

mkPrimOpApp instead of setPrimOpApp

mkExternal instead of setExternal

mkFloat instead of setFloat

Add note that the static mk* function should be removed eventually
2020-12-18 21:48:22 +01:00
Ben Burdette
3edfe6090e missing argument error 2020-11-11 09:29:32 -07:00
Ben Burdette
1d43a6e123 use plain errPos instead of nixCode; fix tests 2020-06-23 15:30:13 -06:00
Ben Burdette
e6f93b94fc Merge branch 'master' into caveman-LOCs 2020-06-18 13:07:53 -06:00
Eelco Dolstra
1fb762d11f Get rid of explicit ErrorInfo constructors 2020-06-15 14:06:58 +02:00
Ben Burdette
6a420d672c print LOC for stdin, string args 2020-05-20 22:18:26 -06:00
Ben Burdette
ec870b9c85 new pos format for more errors 2020-05-12 10:52:26 -06:00
Ben Burdette
b93c1bf3d6 fixes to merged code 2020-05-11 15:52:15 -06:00
Ben Burdette
59b1f5c701 Merge branch 'master' into errors-phase-2 2020-05-11 14:35:30 -06:00
Ben Burdette
e2f61263eb uncrustify formatting 2020-04-29 10:14:32 -06:00
Ben Burdette
e4fb9a3849 remove 'format' from Error constructor calls 2020-04-21 17:07:07 -06:00
Domen Kožar
a693a9fa4b
Attach pos to if expression errors 2020-04-09 09:45:15 +02:00
Silvan Mosberger
c34e96f7e0
Make function arguments retain position info
This allows querying the location of function arguments. E.g.

  builtins.unsafeGetAttrPos "x" (builtins.functionArgs ({ x }: null))

  => { column = 57; file = "/home/infinisil/src/nix/inst/test.nix"; line = 1; }
2020-04-02 05:52:52 +02:00
John Ericson
96e6e680c1 Fix extra ; warnings involving MakeError 2019-11-10 11:24:47 -05:00
Eelco Dolstra
f3c85f9eb3
Revert "Throw a specific error for incomplete parse errors."
This reverts commit 6498adb002. We don't
actually use IncompleteParseError in 'nix repl'.
2018-05-11 11:40:50 +02:00
Eelco Dolstra
53ec5ac69f
Fix some random -Wconversion warnings 2018-05-02 13:56:34 +02:00
Eelco Dolstra
55aa622fb1
Fix compatibility with latest boost::format 2018-03-14 19:25:09 +01:00
Tim Engler
383afab9ad Modified MakeBinOp to no longer produce its name using concatenation and "##".
Doing so prevents emacs tags from working, as well as makes the code extremely
confusing for a newbie.

In the prior state, if someone wants to find the definition of "ExprApp" for
example, a grep through the code reveals nothing. Since the definition could be
hiding in numerous ".h" files, it's really difficult to find. This personally
took me several hours to figure out.
2018-03-09 03:16:33 +00:00
Jörg Thalheim
2fd8f8bb99 Replace Unicode quotes in user-facing strings by ASCII
Relevant RFC: NixOS/rfcs#4

$ ag -l | xargs sed -i -e "/\"/s/’/'/g;/\"/s/‘/'/g"
2017-07-30 12:32:45 +01:00
Eelco Dolstra
215b70f51e
Revert "Get rid of unicode quotes (#1140)"
This reverts commit f78126bfd6. There
really is no need for such a massive change...
2016-11-26 00:38:01 +01:00
Guillaume Maudoux
f78126bfd6 Get rid of unicode quotes (#1140) 2016-11-25 15:48:27 +01:00
Scott Olson
6498adb002 Throw a specific error for incomplete parse errors.
`nix-repl` will use this for deciding whether to keep waiting for input or
error out right away.
2016-02-24 04:32:21 -06:00
Christian Theune
14ebde5289 First hit at providing support for floats in the language. 2016-01-05 00:40:40 +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
ecc2c8f464 Improve printing of ASTs 2014-10-20 09:13:21 +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
11849a320e Use proper quotes everywhere 2014-08-20 18:03:48 +02:00
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
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
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
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
b72c8d2e5b Include position info in function application
This allows error messages like:

  error: the anonymous function at `/etc/nixos/configuration.nix:1:1'
    called without required argument `foo', at
    `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/lib/modules.nix:77:59'
2014-04-04 18:59:29 +02:00
Shea Levy
049a379ec6 The expr of AttrNames/DynamicAttrDefs is always an ExprConcatStrings 2014-03-10 10:14:50 +01:00
Eelco Dolstra
94f9c14d52 Fix some clang warnings 2014-01-21 18:29:55 +01:00
Shea Levy
cd49fe4f9b Don't use any syntactic sugar for dynamic attrs
This doesn't change any functionality but moves some behavior out of the
parser and into the evaluator in order to simplify the code.

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 23:56:26 +00:00
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
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
c897bac549 Make function calls tail-recursive 2013-11-12 11:32:23 +00:00
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
9deb822180 Deduplicate filenames in Pos
This saves ~4 MiB of RAM for NixOS system instantiation, and ~18 MiB
for "nix-env -qa".
2013-10-08 15:36:10 +02:00
Eelco Dolstra
b1e3b1a4ac Treat undefined variable errors consistently
Previously, a undefined variable inside a "with" caused an EvalError
(which can be caught), while outside, it caused a ParseError (which
cannot be caught).  Now both cause an UndefinedVarError (which cannot
be caught).
2013-10-08 14:45:36 +02:00
Eelco Dolstra
6b47de580f Show the exact position of undefined variables
In particular, undefined variable errors in a "with" previously didn't
show *any* position information, so this should help a lot in those
cases.
2013-10-08 14:40:51 +02:00
Eelco Dolstra
221a2daf34 Merge VarRef into ExprVar 2013-10-08 14:24:53 +02:00
Eelco Dolstra
33972629d7 Fix whitespace 2013-09-02 16:29:15 +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
Eelco Dolstra
d308aeaf53 Store Nix integers as longs
So on 64-bit systems, integers are now 64-bit.

Fixes #158.
2013-08-19 12:35:03 +02:00
Eelco Dolstra
18a48d80a0 Show function names in error messages
Functions in Nix are anonymous, but if they're assigned to a
variable/attribute, we can use the variable/attribute name in error
messages, e.g.

while evaluating `concatMapStrings' at `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/strings.nix:18:25':
...
2013-05-16 19:08:02 +02:00
Eelco Dolstra
bdd4646338 Revert "Prevent config.h from being clobbered"
This reverts commit 28bba8c44f.
2013-03-08 01:24:59 +01:00
Eelco Dolstra
28bba8c44f Prevent config.h from being clobbered 2013-03-07 23:55:55 +01:00
Eelco Dolstra
5f18cd2e84 Make "${./path} ..." evaluate to a string, not a path
Wacky string coercion semantics caused expressions like

  exec = "${./my-script} params...";

to evaluate to a path (‘/path/my-script params’), because
anti-quotations are desuged to string concatenation:

  exec = ./my-script + " params...";

By constrast, adding a space at the start would yield a string as
expected:

  exec = " ${./my-script} params...";

Now the first example also evaluates to a string.
2013-02-08 20:04:04 +01:00
Eelco Dolstra
e82767910c Add some basic profiling support to the evaluator
Setting the environment variable NIX_COUNT_CALLS to 1 enables some
basic profiling in the evaluator.  It will count calls to functions
and primops as well as evaluations of attributes.

For example, to see where evaluation of a NixOS configuration spends
its time:

$ NIX_SHOW_STATS=1 NIX_COUNT_CALLS=1 ./src/nix-instantiate/nix-instantiate '<nixos>' -A system --readonly-mode
...
calls to 39 primops:
    239532 head
    233962 tail
    191252 hasAttr
...
calls to 1595 functions:
    224157 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:19'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:14'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:10'
...
evaluations of 7088 attributes:
    167377 undefined position
    132459 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:119:41'
     47322 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:13:21'
...
2012-08-12 23:29:28 -04:00
Eelco Dolstra
b7fd2c2822 Use "#pragma once" to prevent repeated header file inclusion 2012-07-18 14:59:03 -04:00
Eelco Dolstra
9fe24c5a0d * Don't create thunks for simple constants (integers, strings, paths)
and allocate them only once.
* Move Value and related functions into value.hh.
2012-01-07 17:26:33 +00:00
Eelco Dolstra
35f2a6ba82 * Don't use dynamic_cast, it's very slow. "nix-instantiate
/etc/nixos/nixos -A system" spent about 10% of its time in
  dynamic_cast.
2012-01-04 21:24:11 +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
2b9e29b1c8 * Change the right-hand side of the ‘.’ operator from an attribute to
an attribute path.  This is a refactoring to support default values.
2011-07-06 12:28:57 +00:00
Eelco Dolstra
5637037802 * In the ‘?’ operator, allow attribute paths. For instance, you can
write ‘attrs ? a.b’ to test whether ‘attrs’ has an attribute ‘a’
  containing an attribute ‘b’.  This is more convenient than ‘attrs ?
  a && attrs.a ? b’.

  Slight change in the semantics: it's no longer an error if the
  left-hand side of ‘?’ is not an attribute set.  In that case it just
  returns false.  So, ‘null ? foo’ no longer throws an error.
2011-07-06 10:58:17 +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
b2ba62170c * Optimise string constants by putting them in the symbol table. 2010-10-23 21:11:59 +00:00
Eelco Dolstra
41c45a9b31 * Store Value nodes outside of attribute sets. I.e., Attr now stores
a pointer to a Value, rather than the Value directly.  This improves
  the effectiveness of garbage collection a lot: if the Value is
  stored inside the set directly, then any live pointer to the Value
  causes all other attributes in the set to be live as well.
2010-10-22 14:47:42 +00:00
Eelco Dolstra
705868a8a9 * Make sure that config.h is included before the system headers,
because it defines _FILE_OFFSET_BITS.  Without this, on 
  OpenSolaris the system headers define it to be 32, and then 
  the 32-bit stat() ends up being called with a 64-bit "struct 
  stat", or vice versa.

  This also ensures that we get 64-bit file sizes everywhere.

* Remove the redundant call to stat() in parseExprFromFile().
  The file cannot be a symlink because that's the exit condition
  of the loop before.
2010-10-04 17:55:38 +00:00
Eelco Dolstra
89865da76d * Turn build errors during evaluation into EvalErrors. 2010-06-01 11:19:32 +00:00
Eelco Dolstra
01e58adce0 * Store position info for inherited attributes. 2010-05-07 12:43:57 +00:00
Eelco Dolstra
84ce7ac76f * Store attribute positions in the AST and report duplicate attribute
errors with position info.
* For all positions, use the position of the first character of the
  first token, rather than the last character of the first token plus
  one.
2010-05-06 16:46:48 +00:00
Eelco Dolstra
0bc468f195 * Simplify the implementation of `with'. This gives a 7% speedup in
evaluating the NixOS system configuration.
2010-04-22 15:08:09 +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
d39d3c6264 * Implemented inherit. 2010-04-14 23:25:05 +00:00
Eelco Dolstra
81de12bc8f * Refactoring: move variable uses to a separate class. 2010-04-14 15:14:23 +00:00
Eelco Dolstra
110d155778 * Implemented withs. 2010-04-14 15:01:04 +00:00
Eelco Dolstra
9985230c00 * After parsing, compute level/displacement pairs for each variable
use site, allowing environments to be stores as vectors of values
  rather than maps.  This should speed up evaluation and reduce the
  number of allocations.
2010-04-14 14:42:32 +00:00
Eelco Dolstra
816dd3f061 * Remove more obsolete code. 2010-04-14 12:49:05 +00:00
Eelco Dolstra
7d47498b5e * Evaluate lets directly (i.e. without desugaring to `rec { attrs...;
<let-body> = e; }.<let-body>).  This prevents the unnecessary
  allocation of an attribute set.
2010-04-13 13:42:25 +00:00
Eelco Dolstra
ac1e8f40d4 * Use a symbol table to represent identifiers and attribute names
efficiently.  The symbol table ensures that there is only one copy
  of each symbol, thus allowing symbols to be compared efficiently
  using a pointer equality test.
2010-04-13 12:25:42 +00:00
Eelco Dolstra
d4f0b0fc6c * Indented strings. 2010-04-12 22:03:27 +00:00
Eelco Dolstra
a60317f20f * More missing constructs. 2010-04-12 21:21:24 +00:00
Eelco Dolstra
4d6ad5be17 * Don't use ATerms for the abstract syntax trees anymore. Not
finished yet.
2010-04-12 18:30:11 +00:00
Eelco Dolstra
b7b3dd55f9 * Remove a lot of dead code. 2010-04-08 11:41:19 +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
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
5f2492eaec * New primop "throw <string>" to throw an error. This is like abort,
only thrown errors are caught by the top-level derivation evaluation
  in nix-env -qa / -i.
2007-04-16 15:03:19 +00:00
Eelco Dolstra
451dbf687f * nix-env now maintains meta info (from the `meta' derivation
attribute) about installed packages in user environments.  Thus, an
  operation like `nix-env -q --description' shows useful information
  not only on available packages but also on installed packages.

* nix-env now passes the entire manifest as an argument to the Nix
  expression of the user environment builder (not just a list of
  paths), so that in particular the user environment builder has
  access to the meta attributes.
  
* New operation `--set-flag' in nix-env to change meta info of
  installed packages.  This will be useful to pass per-package
  policies to the user environment builder (e.g., how to resolve
  collision or whether to disable a package (NIX-80)) or upgrade
  policies in nix-env (e.g., that a package should be "masked", that
  is, left untouched by upgrade actions).  Example:

  $ nix-env --set-flag enabled false ghc-6.4
2007-02-02 01:52:42 +00:00
Eelco Dolstra
f23dcdd603 * Canonicalise ASTs in `nix-instantiate --eval': remove position
info, sort attribute sets.
2007-01-13 16:17:07 +00:00