Implement block parameters

Fixes #907

spec/builtins.js

@@ -122,6 +122,16 @@ describe('builtin helpers', function() {
       equal(result, "0. goodbye! 0 1 2 After 0 1. Goodbye! 0 1 2 After 1 2. GOODBYE! 0 1 2 After 2 cruel world!", "The @index variable is used");
     });
 
+    it('each with block params', function() {
+      var string = '{{#each goodbyes as |value index|}}{{index}}. {{value.text}}! {{#each ../goodbyes as |childValue childIndex|}} {{index}} {{childIndex}}{{/each}} After {{index}} {{/each}}{{index}}cruel {{world}}!';
+      var hash   = {goodbyes: [{text: 'goodbye'}, {text: 'Goodbye'}], world: 'world'};
+
+      var template = CompilerContext.compile(string);
+      var result = template(hash);
+
+      equal(result, '0. goodbye!  0 0 0 1 After 0 1. Goodbye!  1 0 1 1 After 1 cruel world!');
+    });
+
     it("each object with @index", function() {
       var string = "{{#each goodbyes}}{{@index}}. {{text}}! {{/each}}cruel {{world}}!";
       var hash   = {goodbyes: {'a': {text: "goodbye"}, b: {text: "Goodbye"}, c: {text: "GOODBYE"}}, world: "world"};

spec/helpers.js

@@ -657,4 +657,64 @@ describe('helpers', function() {
       equals(result, "GOODBYE cruel WORLD goodbye", "Helper executed");
     });
   });
+
+  describe('block params', function() {
+    it('should take presedence over context values', function() {
+      var hash = {value: 'foo'};
+      var helpers = {
+        goodbyes: function(options) {
+          equals(options.fn.blockParams, 1);
+          return options.fn({value: 'bar'}, {blockParams: [1, 2]});
+        }
+      };
+      shouldCompileTo('{{#goodbyes as |value|}}{{value}}{{/goodbyes}}{{value}}', [hash, helpers], '1foo');
+    });
+    it('should take presedence over helper values', function() {
+      var hash = {};
+      var helpers = {
+        value: function() {
+          return 'foo';
+        },
+        goodbyes: function(options) {
+          equals(options.fn.blockParams, 1);
+          return options.fn({}, {blockParams: [1, 2]});
+        }
+      };
+      shouldCompileTo('{{#goodbyes as |value|}}{{value}}{{/goodbyes}}{{value}}', [hash, helpers], '1foo');
+    });
+    it('should not take presedence over pathed values', function() {
+      var hash = {value: 'bar'};
+      var helpers = {
+        value: function() {
+          return 'foo';
+        },
+        goodbyes: function(options) {
+          equals(options.fn.blockParams, 1);
+          return options.fn(this, {blockParams: [1, 2]});
+        }
+      };
+      shouldCompileTo('{{#goodbyes as |value|}}{{./value}}{{/goodbyes}}{{value}}', [hash, helpers], 'barfoo');
+    });
+    it('should take presednece over parent block params', function() {
+      var hash = {value: 'foo'},
+          value = 1;
+      var helpers = {
+        goodbyes: function(options) {
+          return options.fn({value: 'bar'}, {blockParams: options.fn.blockParams === 1 ? [value++, value++] : undefined});
+        }
+      };
+      shouldCompileTo('{{#goodbyes as |value|}}{{#goodbyes}}{{value}}{{#goodbyes as |value|}}{{value}}{{/goodbyes}}{{/goodbyes}}{{/goodbyes}}{{value}}', [hash, helpers], '13foo');
+    });
+
+    it('should allow block params on chained helpers', function() {
+      var hash = {value: 'foo'};
+      var helpers = {
+        goodbyes: function(options) {
+          equals(options.fn.blockParams, 1);
+          return options.fn({value: 'bar'}, {blockParams: [1, 2]});
+        }
+      };
+      shouldCompileTo('{{#if bar}}{{else goodbyes as |value|}}{{value}}{{/if}}{{value}}', [hash, helpers], '1foo');
+    });
+  });
 });

spec/runtime.js

@@ -48,6 +48,16 @@ describe('runtime', function() {
         template._child(1);
       }, Error, 'must pass parent depths');
     });
+
+    it('should throw for block param methods without params', function() {
+      shouldThrow(function() {
+        var template = Handlebars.compile('{{#foo as |foo|}}{{foo}}{{/foo}}');
+        // Calling twice to hit the non-compiled case.
+        template._setup({});
+        template._setup({});
+        template._child(1);
+      }, Error, 'must pass block params');
+    });
     it('should expose child template', function() {
       var template = Handlebars.compile('{{#foo}}bar{{/foo}}');
         // Calling twice to hit the non-compiled case.
@@ -57,7 +67,7 @@ describe('runtime', function() {
     it('should render depthed content', function() {
       var template = Handlebars.compile('{{#foo}}{{../bar}}{{/foo}}');
         // Calling twice to hit the non-compiled case.
-      equal(template._child(1, undefined, [{bar: 'baz'}])(), 'baz');
+      equal(template._child(1, undefined, [], [{bar: 'baz'}])(), 'baz');
     });
   });
 

spec/track-ids.js

@@ -106,6 +106,27 @@ describe('track ids', function() {
     equals(template(context, {helpers: helpers}), 'HELP ME MY BOSS 1');
   });
 
+  it('should use block param paths', function() {
+    var template = CompilerContext.compile('{{#doIt as |is|}}{{wycats is.a slave.driver is}}{{/doIt}}', {trackIds: true});
+
+    var helpers = {
+      doIt: function(options) {
+        var blockParams = [this.is];
+        blockParams.path = ['zomg'];
+        return options.fn(this, {blockParams: blockParams});
+      },
+      wycats: function(passiveVoice, noun, blah, options) {
+        equal(options.ids[0], 'zomg.a');
+        equal(options.ids[1], 'slave.driver');
+        equal(options.ids[2], 'zomg');
+
+        return "HELP ME MY BOSS " + options.ids[0] + ':' + passiveVoice + ' ' + options.ids[1] + ':' + noun;
+      }
+    };
+
+    equals(template(context, {helpers: helpers}), 'HELP ME MY BOSS zomg.a:foo slave.driver:bar');
+  });
+
   describe('builtin helpers', function() {
     var helpers = {
       wycats: function(name, options) {
@@ -129,6 +150,17 @@ describe('track ids', function() {
 
         equals(template({array: [{name: 'foo'}, {name: 'bar'}]}, {helpers: helpers}), 'foo:.array..0\nbar:.array..1\n');
       });
+      it('should handle block params', function() {
+        var helpers = {
+          wycats: function(name, options) {
+            return name + ':' + options.ids[0] + '\n';
+          }
+        };
+
+        var template = CompilerContext.compile('{{#each array as |value|}}{{wycats value.name}}{{/each}}', {trackIds: true});
+
+        equals(template({array: [{name: 'foo'}, {name: 'bar'}]}, {helpers: helpers}), 'foo:array.0.name\nbar:array.1.name\n');
+      });
     });
     describe('#with', function() {
       it('should track contextPath', function() {