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70 commits

Author SHA1 Message Date
Eelco Dolstra
0ed89c569f * Fix the parsing of
''
      '${foo}'
    ''
    
  where the antiquote should work as expected, instead of giving the
  string "'${foo}'".
2008-02-05 13:38:07 +00:00
Eelco Dolstra
b42ef9c054 * Syntax to escape '', ${. 2007-12-06 10:20:58 +00:00
Eelco Dolstra
6d6c68c0d2 * Added a new kind of multi-line string literal delimited by two
single quotes.  Example (from NixOS):

    job = ''
      start on network-interfaces

      start script

        rm -f /var/run/opengl-driver
        ${if videoDriver == "nvidia"        
          then "ln -sf ${nvidiaDrivers} /var/run/opengl-driver"
          else if cfg.driSupport
          then "ln -sf ${mesa} /var/run/opengl-driver"
          else ""
        }

        rm -f /var/log/slim.log

      end script
    '';

  This style has two big advantages:

  - \, ' and " aren't special, only '' and ${.  So you get a lot less
    escaping in shell scripts / configuration files in Nixpkgs/NixOS.
    The delimiter '' is rare in scripts (and can usually be written as
    "").  ${ is also fairly rare.

    Other delimiters such as <<...>>, {{...}} and <|...|> were also
    considered but this one appears to have the fewest drawbacks
    (thanks Martin).

  - Indentation is intelligently stripped so that multi-line strings
    can follow the nesting structure of the containing Nix
    expression.  E.g. in the example above 6 spaces are stripped from
    the start of each line.  This prevents unnecessary indentation in
    generated files (which sometimes even breaks things).

  See tests/lang/eval-okay-ind-string.nix for some examples.
2007-11-30 16:48:45 +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
ac19b333b3 * Finally, a real "let" syntax: `let x = ...; ... z = ...; in ...'. 2006-10-02 15:52:44 +00:00
Eelco Dolstra
7581cfdee4 * Hack for Bison 2.3 compatability. 2006-10-02 14:43:15 +00:00
Eelco Dolstra
e3ce954582 * Compile the lexer as C++ code. Remove all the redundant C/C++
marshalling code.
2006-09-04 21:36:15 +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
de90fdf908 * Allow "$" in strings as long as they are not followed by "{". (Too
bad flex doesn't have lexical restrictions, the current solution
  isn't quite right...)
2006-09-01 12:04:06 +00:00
Eelco Dolstra
2670642733 * Handle carriage returns. Fixes NIX-53. 2006-08-16 10:28:44 +00:00
Eelco Dolstra
7276e194ee * Disallow unescaped $ in string literals. 2006-05-01 15:29:46 +00:00
Eelco Dolstra
0064599a27 * String interpolation. Expressions like
"--with-freetype2-library=" + freetype + "/lib"

  can now be written as

    "--with-freetype2-library=${freetype}/lib"

  An arbitrary expression can be enclosed within ${...}, not just
  identifiers.

* Escaping in string literals: \n, \r, \t interpreted as in C, any
  other character following \ is interpreted as-is.
  
* Newlines are now allowed in string literals.
2006-05-01 14:01:47 +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
3277c9432a * Bug fix in parsing of /* ... */ comments; due to longest match
regexp there could be only one such comment per file.
2004-10-27 13:00:31 +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
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
9d25466b34 * An attribute set update operator (//). E.g.,
{x=1; y=2; z=3;} // {y=4;}  =>  {x=1; y=4; z=3;}
2004-02-04 16:49:51 +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
619f20775d * Parser numbers again.
* Include missing files in distributions.
2004-01-30 17:06:03 +00:00
Eelco Dolstra
c5baaafae6 * Replaced the SDF parser by a substantially faster Bison/Flex
parser (roughly 80x faster).

  The absolutely latest version of Bison (1.875c) is required for
  reentrant GLR support, as well as a recent version of Flex (say,
  2.5.31).  Note that most Unix distributions ship with the
  prehistoric Flex 2.5.4, which doesn't support reentrancy.
2004-01-30 15:21:42 +00:00