Merge pull request #928 from STRML/constPragma

Mark vars with /** @const */ pragma as consts so they can be eliminated.

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/scope.js b/lib/scope.js
index 5e93020f..4cea5176 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -94,6 +94,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     var scope = self.parent_scope = null;
     var labels = new Dictionary();
     var defun = null;
+    var last_var_had_const_pragma = false;
     var nesting = 0;
     var tw = new TreeWalker(function(node, descend){
         if (options.screw_ie8 && node instanceof AST_Catch) {
@@ -151,10 +152,13 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             // later.
             (node.scope = defun.parent_scope).def_function(node);
         }
+        else if (node instanceof AST_Var) {
+            last_var_had_const_pragma = node.has_const_pragma();
+        }
         else if (node instanceof AST_SymbolVar
                  || node instanceof AST_SymbolConst) {
             var def = defun.def_variable(node);
-            def.constant = node instanceof AST_SymbolConst;
+            def.constant = node instanceof AST_SymbolConst || last_var_had_const_pragma;
             def.init = tw.parent().value;
         }
         else if (node instanceof AST_SymbolCatch) {
@@ -357,6 +361,12 @@ AST_Symbol.DEFMETHOD("global", function(){
     return this.definition().global;
 });
 
+AST_Var.DEFMETHOD("has_const_pragma", function() {
+    var comments_before = this.start && this.start.comments_before;
+    var lastComment = comments_before && comments_before[comments_before.length - 1];
+    return lastComment && /@const\b/.test(lastComment.value);
+});
+
 AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options){
     return defaults(options, {
         except      : [],