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authorEelco Dolstra <e.dolstra@tudelft.nl>2005-07-25T15·05+0000
committerEelco Dolstra <e.dolstra@tudelft.nl>2005-07-25T15·05+0000
commit991a130b1e71b3b849b3640264f8834d6e13da22 (patch)
tree1e99a52b73043814fa501c8d470a933d2bc7cded /src/libexpr/eval.cc
parente6899794ae9ce3924b818721d5caff463bccd60c (diff)
* Added a list concatenation operator:
    [1 2 3] ++ [4 5 6] => [1 2 3 4 5 6]

Diffstat (limited to 'src/libexpr/eval.cc')
-rw-r--r--src/libexpr/eval.cc16
1 files changed, 16 insertions, 0 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index d4593b5c0ec0..9a6d414db706 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -140,6 +140,15 @@ bool evalBool(EvalState & state, Expr e)
 }
 
 
+ATermList evalList(EvalState & state, Expr e)
+{
+    e = evalExpr(state, e);
+    ATermList list;
+    if (!matchList(e, list)) throw Error("list expected");
+    return list;
+}
+
+
 Expr evalExpr2(EvalState & state, Expr e)
 {
     Expr e1, e2, e3, e4;
@@ -336,6 +345,13 @@ Expr evalExpr2(EvalState & state, Expr e)
         else throw Error("wrong argument types in `+' operator");
     }
 
+    /* List concatenation. */
+    if (matchOpConcat(e, e1, e2)) {
+        ATermList l1 = evalList(state, e1);
+        ATermList l2 = evalList(state, e2);
+        return makeList(ATconcat(l1, l2));
+    }
+
     /* Barf. */
     throw badTerm("invalid expression", e);
 }