* Added an operator `~' to select paths within a derivation. E.g.,

    {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'.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index 44d1e06abe..b1fe9e0931 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -44,6 +44,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s)
 %nonassoc EQ NEQ
 %right UPDATE
 %left NEG
+%nonassoc '~'
 
 %%
 
@@ -79,6 +80,7 @@ expr_op
   | expr_op OR expr_op { $$ = ATmake("OpOr(<term>, <term>)", $1, $3); }
   | expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); }
   | expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(<term>, <term>)", $1, $3); }
+  | expr_op '~' expr_op { $$ = ATmake("SubPath(<term>, <term>)", $1, $3); }
   | expr_app
   ;