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2004-04-05* When something goes wrong in the evaluation of a Nix expression,Eelco Dolstra
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.
2004-04-02* Print a more useful error message in case of an invalid derivationEelco Dolstra
binding.
2004-03-30* The recent change in nixpkgs of calling `stdenv.mkDerivation'Eelco Dolstra
instead of `derivation' triggered a huge slowdown in the Nix expression evaluator. Total execution time of `nix-env -qa' went up by a factor of 60 or so. This scalability problem was caused by expressions such as (x: y: ... x ...) a b where `a' is a large term (say, the one in `all-packages-generic.nix'). Then the first beta-reduction would produce (y: ... a ...) b by substituting `a' for `x'. The second beta-reduction would then substitute `b' for `y' into the body `... a ...', which is a large term due to `a', and thus causes a large traversal to be performed by substitute() in the second reduction. This is however entirely redundant, since `a' cannot contain free variables (since we never substitute below a weak head normal form). The solution is to wrap substituted terms into a `Closed' constructor, i.e., subst(subs, Var(x)) = Closed(e) iff subs[x] = e have substitution not descent into closed terms, subst(subs, Closed(x)) = Closed(x) and otherwise ignore them for evaluation, eval(Closed(x)) = eval(x). * Fix a typo that caused incorrect substitutions to be performed in simple lambdas, e.g., `(x: x: x) a' would reduce to `(x: a)'.
2004-03-28* Added an operator `?' to test for attribute existence, e.g.,Eelco Dolstra
`attrs ? x' yields true iff `attrs' has an attribute named `x'.
2004-03-28* Added an operator `~' to select paths within a derivation. E.g.,Eelco Dolstra
{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* Added plain lambdas, e.g., `let { id = x: x; const = x: y: x; }'.Eelco Dolstra
`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]; ...
2004-03-19* `null' is a normal form.Eelco Dolstra
2004-02-19* Resolve an ambiguity between ifs and attribute selection, e.g., `ifEelco Dolstra
b then x else y.z'.
2004-02-16* Allow linking against an external Berkeley DB / ATerm library.Eelco Dolstra
2004-02-16* Inherited attributes in recursive attribute sets are in scope of theEelco Dolstra
non-inherited attributes.
2004-02-04* Extended the `inherit' syntax to optionally select attributes fromEelco Dolstra
other attribute sets, rather than the current scope. E.g., {inherit (pkgs) gcc binutils;} is equivalent to {gcc = pkgs.gcc; binutils = pkgs.binutils;} I am not so happy about the syntax.
2004-02-04* An attribute set update operator (//). E.g.,Eelco Dolstra
{x=1; y=2; z=3;} // {y=4;} => {x=1; y=4; z=3;}
2004-02-04* Use a map to lookup primops.Eelco Dolstra
* Various performance improvements in the evaluator. * Do not link against unused (and missing!) libraries (-lsglr, etc.).
2004-02-03* Verify that all variables in a Nix expression are defined.Eelco Dolstra
2004-02-02* Added syntactic sugar to the construction of attribute sets toEelco Dolstra
`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}'.
2004-01-30* Doh!Eelco Dolstra
2004-01-30* Parser numbers again.Eelco Dolstra
* Include missing files in distributions.
2004-01-30* Detect flex and bison; updated the manual.Eelco Dolstra
2004-01-30* Replaced the SDF parser by a substantially faster Bison/FlexEelco Dolstra
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.
2004-01-29* Optimised the SDF grammar.Eelco Dolstra
2004-01-21* Fixed a subtle uninitialised variable bug in ATermMaps copied fromEelco Dolstra
ATermMaps. Found thanks to Valgrind!
2004-01-15* Catch SIGINT to terminate cleanly when the user tries to interruptEelco Dolstra
Nix. This is to prevent Berkeley DB from becoming wedged. Unfortunately it is not possible to throw C++ exceptions from a signal handler. In fact, you can't do much of anything except change variables of type `volatile sig_atomic_t'. So we set an interrupt flag in the signal handler and check it at various strategic locations in the code (by calling checkInterrupt()). Since this is unlikely to cover all cases (e.g., (semi-)infinite loops), sometimes SIGTERM may now be required to kill Nix.
2004-01-15* Obsolete.Eelco Dolstra
2004-01-05* Implemented Eelco V.'s `nix-env -I' command to specify the defaultEelco Dolstra
path of the Nix expression to be used with the import, upgrade, and query commands. For instance, $ nix-env -I ~/nixpkgs/pkgs/system/i686-linux.nix $ nix-env --query --available [aka -qa] sylpheed-0.9.7 bison-1.875 pango-1.2.5 subversion-0.35.1 ... $ nix-env -i sylpheed $ nix-env -u subversion There can be only one default at a time. * If the path to a Nix expression is a symlink, follow the symlink prior to resolving relative path references in the expression.
2003-11-25* More `make dist' fixes.Eelco Dolstra
2003-11-25* Allow integer bindings in derivations.Eelco Dolstra
2003-11-22* Maintain integrity of the substitute and successor mappings whenEelco Dolstra
deleting a path in the store. * Allow absolute paths in Nix expressions. * Get nix-prefetch-url to work again. * Various other fixes.
2003-11-21* Uninstallation.Eelco Dolstra
2003-11-19* nix-env: a tool to manage user environments.Eelco Dolstra
* Replace all directory reading code by a generic readDirectory() function.
2003-11-19* Refactoring (step 2).Eelco Dolstra
2003-11-19* Refactoring: put the Nix expression evaluator in its own library soEelco Dolstra
that it can be used by multiple programs.