1 files changed, 19 insertions, 3 deletions

diff --git a/lib/ast.js b/lib/ast.js
index f496095a..f75670e6 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -118,9 +118,25 @@ var AST_Node = DEFNODE("Node", "start end", {
     }
 }, null);
 
-AST_Node.warn = function(txt, props) {
-    if (AST_Node.warn_function) AST_Node.warn_function(string_template(txt, props));
-};
+(AST_Node.log_function = function(fn, verbose) {
+    var printed = Object.create(null);
+    if (fn) {
+        AST_Node.info = verbose ? function(text, props) {
+            log("INFO: " + string_template(text, props));
+        } : noop;
+        AST_Node.warn = function(text, props) {
+            log("WARN: " + string_template(text, props));
+        };
+    } else {
+        AST_Node.info = AST_Node.warn = noop;
+    }
+
+    function log(msg) {
+        if (printed[msg]) return;
+        printed[msg] = true;
+        fn(msg);
+    }
+})();
 
 /* -----[ statements ]----- */