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authorEelco Dolstra <e.dolstra@tudelft.nl>2004-03-19T14·45+0000
committerEelco Dolstra <e.dolstra@tudelft.nl>2004-03-19T14·45+0000
commit79bb0008ec9afa8d8cee9e6b807a579bcb1c92ab (patch)
treec2874f394da9d9de0ce37dc031914ba140afdb58
parente6253b58cdb6b3836a616821b7f5dc66790ac989 (diff)
* `null' is a normal form.
-rw-r--r--src/libexpr/eval.cc19
1 files changed, 11 insertions, 8 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 335f44baacf4..7ee157c316ac 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -186,14 +186,17 @@ Expr evalExpr2(EvalState & state, Expr e)
     ATerm name;
 
     /* Normal forms. */
-    if (atMatch(m, e) >> "Str" ||
-        atMatch(m, e) >> "Path" ||
-        atMatch(m, e) >> "Uri" ||
-        atMatch(m, e) >> "Int" ||
-        atMatch(m, e) >> "Bool" ||
-        atMatch(m, e) >> "Function" ||
-        atMatch(m, e) >> "Attrs" ||
-        atMatch(m, e) >> "List")
+    string cons;
+    if (atMatch(m, e) >> cons &&
+        (cons == "Str" ||
+         cons == "Path" ||
+         cons == "Uri" ||
+         cons == "Null" ||
+         cons == "Int" ||
+         cons == "Bool" ||
+         cons == "Function" ||
+         cons == "Attrs" ||
+         cons == "List"))
         return e;
 
     /* Any encountered variables must be undeclared or primops. */