re-introduce `enclose` (#3163)

fixes #2443

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/ast.js b/lib/ast.js
index 331d340b..1a77a59d 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -335,6 +335,23 @@ var AST_Toplevel = DEFNODE("Toplevel", "globals", {
             }
         }));
         return wrapped_tl;
+    },
+    wrap_enclose: function(args_values) {
+        if (typeof args_values != "string") args_values = "";
+        var index = args_values.indexOf(":");
+        if (index < 0) index = args_values.length;
+        var body = this.body;
+        return parse([
+            "(function(",
+            args_values.slice(0, index),
+            '){"$ORIG"})(',
+            args_values.slice(index + 1),
+            ")"
+        ].join("")).transform(new TreeTransformer(function(node) {
+            if (node instanceof AST_Directive && node.value == "$ORIG") {
+                return MAP.splice(body);
+            }
+        }));
     }
 }, AST_Scope);