Add builtin function "partition"

The implementation of "partition" in Nixpkgs is O(n^2) (because of the
use of ++), and for some reason was causing stack overflows in
multi-threaded evaluation (not sure why).

This reduces "nix-env -qa --drv-path" runtime by 0.197s and memory
usage by 298 MiB (in non-Boehm mode).

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
index f5e485748812..048522016c62 100644
--- a/src/libexpr/value.hh
+++ b/src/libexpr/value.hh
@@ -250,4 +250,13 @@ void mkPath(Value & v, const char * s);
 size_t valueSize(Value & v);
 
 
+#if HAVE_BOEHMGC
+typedef std::vector<Value *, gc_allocator<Value *> > ValueVector;
+typedef std::map<Symbol, Value *, std::less<Symbol>, gc_allocator<Value *> > ValueMap;
+#else
+typedef std::vector<Value *> ValueVector;
+typedef std::map<Symbol, Value *> ValueMap;
+#endif
+
+
 }