From 9279174dde3e1a450e63e866d2683352dd8238d3 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Thu, 14 Aug 2008 14:00:44 +0000 Subject: * 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). --- src/libexpr/nixexpr.cc | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'src/libexpr/nixexpr.cc') diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc index b2d775abb..d96b5be97 100644 --- a/src/libexpr/nixexpr.cc +++ b/src/libexpr/nixexpr.cc @@ -114,12 +114,13 @@ static void varsBoundByPattern(ATermMap & map, Pattern pat) { ATerm name; ATermList formals; - Pattern pat1, pat2; + Pattern pat1, pat2; + ATermBool ellipsis; /* Use makeRemoved() so that it can be used directly in substitute(). */ if (matchVarPat(pat, name)) map.set(name, makeRemoved()); - else if (matchAttrsPat(pat, formals)) { + else if (matchAttrsPat(pat, formals, ellipsis)) { for (ATermIterator i(formals); i; ++i) { ATerm d1; if (!matchFormal(*i, name, d1)) abort(); -- cgit v1.2.3