implement concat

1 files changed, 14 insertions, 0 deletions

diff --git a/interpreter.py b/interpreter.py
index 4677432..841f5cf 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -263,6 +263,20 @@ def interpretToString(expr, env):
 
 GLOBALS.register("->string", Builtin(interpretToString, 1))
 
+def interpretConcat(expr, env):
+    # concat str1 str2...strN
+    if len(expr.args) < 2:
+        raise Exception("'concat' takes at least two arguments")
+    out = ""
+    for arg in expr.args:
+        tmp = evaluate(arg, env)
+        if not isinstance(tmp, str):
+            raise Exception("'concat' arguments must be strings")
+        out += tmp
+    return out
+
+GLOBALS.register("concat", Builtin(interpretConcat))
+
 def interpretForCount(expr, env):
     # for-count int exprs
     num = evaluate(expr.args[0], env)