* builtins.substring: if "start" is beyond the end of the string,

return the empty string.
2011-01-14 12:47:10 +00:00 · 2011-01-14 12:47:10 +00:00 · 9db190eb31
commit 9db190eb31
parent d6c8b995c5
3 changed files with 4 additions and 2 deletions
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@ -965,7 +965,7 @@ static void prim_substring(EvalState & state, Value * * args, Value & v)

    if (start < 0) throw EvalError("negative start position in `substring'");

-    mkString(v, string(s, start, len), context);
+    mkString(v, start >= s.size() ? "" : string(s, start, len), context);
 }


--- a/tests/lang/eval-okay-substring.exp
+++ b/tests/lang/eval-okay-substring.exp
@ -1 +1 @@
-"ooxfoobarybarzobaabb"
+"ooxfoobarybarzobaabbc"
--- a/tests/lang/eval-okay-substring.nix
+++ b/tests/lang/eval-okay-substring.nix
@ -17,3 +17,5 @@ substring 1 2 s
 + substring 3 0 s
 + "b"
 + substring 3 1 s
+ "c"
+ substring 5 10 "perl"