Rework has_directive

It's now available during tree walking, i.e. walker.has_directive("use
asm"), rather than as part of the scope.  It's thus no longer necessary
to call `figure_out_scope` before codegen.  Added special bits in the
code generator to overcome the fact that it doesn't inherit from
TreeWalker.

Fix #861

1 files changed, 24 insertions, 6 deletions

diff --git a/lib/ast.js b/lib/ast.js
index e7952847..f5225d78 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -85,7 +85,7 @@ function DEFNODE(type, props, methods, base) {
     return ctor;
 };
 
-var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos nlb comments_before file", {
+var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos nlb comments_before file literal", {
 }, null);
 
 var AST_Node = DEFNODE("Node", "start end", {
@@ -927,27 +927,36 @@ var AST_True = DEFNODE("True", null, {
 function TreeWalker(callback) {
     this.visit = callback;
     this.stack = [];
+    this.directives = Object.create(null);
 };
 TreeWalker.prototype = {
     _visit: function(node, descend) {
-        this.stack.push(node);
+        this.push(node);
         var ret = this.visit(node, descend ? function(){
             descend.call(node);
         } : noop);
         if (!ret && descend) {
             descend.call(node);
         }
-        this.stack.pop();
+        this.pop(node);
         return ret;
     },
     parent: function(n) {
         return this.stack[this.stack.length - 2 - (n || 0)];
     },
     push: function (node) {
+        if (node instanceof AST_Lambda) {
+            this.directives = Object.create(this.directives);
+        } else if (node instanceof AST_Directive) {
+            this.directives[node.value] = this.directives[node.value] ? "up" : true;
+        }
         this.stack.push(node);
     },
-    pop: function() {
-        return this.stack.pop();
+    pop: function(node) {
+        this.stack.pop();
+        if (node instanceof AST_Lambda) {
+            this.directives = Object.getPrototypeOf(this.directives);
+        }
     },
     self: function() {
         return this.stack[this.stack.length - 1];
@@ -960,7 +969,16 @@ TreeWalker.prototype = {
         }
     },
     has_directive: function(type) {
-        return this.find_parent(AST_Scope).has_directive(type);
+        var dir = this.directives[type];
+        if (dir) return dir;
+        var node = this.stack[this.stack.length - 1];
+        if (node instanceof AST_Scope) {
+            for (var i = 0; i < node.body.length; ++i) {
+                var st = node.body[i];
+                if (!(st instanceof AST_Directive)) break;
+                if (st.value == type) return true;
+            }
+        }
     },
     in_boolean_context: function() {
         var stack = this.stack;