Add support for inverted sections in the parser

lib/handlebars/ast.js

@@ -21,10 +21,11 @@ Handlebars.AST.PartialNode = function(id, context) {
   this.context = context;
 };
 
-Handlebars.AST.BlockNode = function(mustache, program) {
+Handlebars.AST.BlockNode = function(mustache, program, inverted) {
   this.type = "block";
   this.mustache = mustache;
   this.program  = program;
+  this.inverted = inverted;
 };
 
 Handlebars.AST.ContentNode = function(string) {

lib/handlebars/printer.js

@@ -50,7 +50,7 @@ Handlebars.PrintVisitor.prototype.program = function(program) {
 Handlebars.PrintVisitor.prototype.block = function(block) {
   var out = "";
 
-  out = out + this.pad("BLOCK:");
+  out = out + (block.inverted ? this.pad("INVERSE:") : this.pad("BLOCK:"));
   this.padding++;
   out = out + this.accept(block.mustache);
   out = out + this.accept(block.program);

spec/parser_spec.rb

@@ -55,8 +55,8 @@ describe "Parser" do
       with_padding { yield }
     end
 
-    def block
-      pad("BLOCK:")
+    def block(inverse = false)
+      inverse ? pad("INVERSE:") : pad("BLOCK:")
       with_padding { yield }
     end
 
@@ -148,6 +148,18 @@ describe "Parser" do
     end
   end
 
+  it "parses a standalone inverse section" do
+    ast_for("{{^foo}}bar{{/baz}}").should == program do
+      block true do
+        mustache id("foo")
+
+        program do
+          content "bar"
+        end
+      end
+    end
+  end
+
   it "raises if there's a Parse error" do
     lambda { ast_for("{{foo}") }.should   raise_error(V8::JSError, /Parse error on line 1/)
     lambda { ast_for("{{foo &}}")}.should raise_error(V8::JSError, /Parse error on line 1/)

spec/spec_helper.rb

@@ -42,6 +42,10 @@ module Handlebars
       context.load('lib/handlebars/runtime.js')
       context.load('lib/handlebars/utils.js')
       context.load('lib/handlebars.js')
+
+      context["p"] = proc do |val|
+        p val
+      end
     end
   end
 end

src/handlebars.yy

@@ -18,7 +18,8 @@ statements
   ;
 
 statement
-  : openBlock program closeBlock { $$ = new yy.BlockNode($1, $2) }
+  : openInverse program closeBlock { $$ = new yy.BlockNode($1, $2, true) }
+  | openBlock program closeBlock { $$ = new yy.BlockNode($1, $2, false) }
   | mustache { $$ = $1 }
   | partial { $$ = $1 }
   | CONTENT { $$ = new yy.ContentNode($1) }
@@ -29,6 +30,10 @@ openBlock
   : OPEN_BLOCK inMustache CLOSE { $$ = new yy.MustacheNode($2) }
   ;
 
+openInverse
+  : OPEN_INVERSE inMustache CLOSE { $$ = new yy.MustacheNode($2) }
+  ;
+
 closeBlock
   : OPEN_ENDBLOCK path CLOSE { }
   ;