more AST_If optimizations

1 files changed, 11 insertions, 2 deletions

diff --git a/lib/utils.js b/lib/utils.js
index e9a2f80a..6f8334ee 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -113,6 +113,8 @@ var MAP = (function(){
         var ret = [], top = [], i;
         function doit() {
             var val = f.call(o, a[i], i);
+            var is_last = val instanceof Last;
+            if (is_last) val = val.v;
             if (val instanceof AtTop) {
                 val = val.v;
                 if (val instanceof Splice) {
@@ -128,16 +130,23 @@ var MAP = (function(){
                     ret.push(val);
                 }
             }
+            return is_last;
         };
-        if (a instanceof Array) for (i = 0; i < a.length; ++i) doit();
-        else for (i in a) if (HOP(a, i)) doit();
+        if (a instanceof Array) {
+            for (i = 0; i < a.length; ++i) if (doit()) break;
+        }
+        else {
+            for (i in a) if (HOP(a, i)) if (doit()) break;
+        }
         return top.concat(ret);
     };
     MAP.at_top = function(val) { return new AtTop(val) };
     MAP.splice = function(val) { return new Splice(val) };
+    MAP.last = function(val) { return new Last(val) };
     var skip = MAP.skip = {};
     function AtTop(val) { this.v = val };
     function Splice(val) { this.v = val };
+    function Last(val) { this.v = val };
     return MAP;
 })();