Add support for dynamic partial names

docs/compiler-api.md

@@ -55,15 +55,21 @@ interface Statement <: Node { }
 
 interface MustacheStatement <: Statement {
     type: "MustacheStatement";
-    sexpr: SubExpression;
-    escaped: boolean;
 
+    path: PathExpression;
+    params: [ Expression ];
+    hash: Hash;
+
+    escaped: boolean;
     strip: StripFlags | null;
 }
 
 interface BlockStatement <: Statement {
     type: "BlockStatement";
-    sexpr: SubExpression;
+    path: PathExpression;
+    params: [ Expression ];
+    hash: Hash;
+
     program: Program | null;
     inverse: Program | null;
 
@@ -74,12 +80,19 @@ interface BlockStatement <: Statement {
 
 interface PartialStatement <: Statement {
     type: "PartialStatement";
-    sexpr: SubExpression;
+    name: PathExpression | SubExpression;
+    params: [ Expression ];
+    hash: Hash;
 
     indent: string;
     strip: StripFlags | null;
 }
+```
+
+`name` will be a `SubExpression` when tied to a dynamic partial, i.e. `{{> (foo) }}`, otherwise this is a path or literal whose `original` value is used to lookup the desired partial.
+
 
+```java
 interface ContentStatement <: Statement {
     type: "ContentStatement";
     value: string;
@@ -108,13 +121,9 @@ interface SubExpression <: Expression {
     path: PathExpression;
     params: [ Expression ];
     hash: Hash;
-
-    isHelper: true | null;
 }
 ```
 
-`isHelper` is not required and is used to disambiguate between cases such as `{{foo}}` and `(foo)`, which have slightly different call behaviors.
-
 ##### Paths
 
 ```java
@@ -195,7 +204,7 @@ function ImportScanner() {
 ImportScanner.prototype = new Visitor();
 
 ImportScanner.prototype.PartialStatement = function(partial) {
-  this.partials.push({request: partial.sexpr.original});
+  this.partials.push({request: partial.name.original});
 
   Visitor.prototype.PartialStatement.call(this, partial);
 };
@@ -221,6 +230,8 @@ The `Handlebars.JavaScriptCompiler` object has a number of methods that may be c
   - `name` is the current path component
   - `type` is the type of name being evaluated. May be one of `context`, `data`, `helper`, or `partial`.
 
+  Note that this does not impact dynamic partials, which implementors need to be aware of. Overriding `VM.resolvePartial` may be required to support dynamic cases.
+
 - `depthedLookup(name)`
   Used to generate code that resolves parameters within any context in the stack. Is only used in `compat` mode. 
 

lib/handlebars/compiler/ast.js

@@ -8,21 +8,25 @@ var AST = {
     this.strip = strip;
   },
 
-  MustacheStatement: function(sexpr, escaped, strip, locInfo) {
+  MustacheStatement: function(path, params, hash, escaped, strip, locInfo) {
     this.loc = locInfo;
     this.type = 'MustacheStatement';
 
-    this.sexpr = sexpr;
+    this.path = path;
+    this.params = params || [];
+    this.hash = hash;
     this.escaped = escaped;
 
     this.strip = strip;
   },
 
-  BlockStatement: function(sexpr, program, inverse, openStrip, inverseStrip, closeStrip, locInfo) {
+  BlockStatement: function(path, params, hash, program, inverse, openStrip, inverseStrip, closeStrip, locInfo) {
     this.loc = locInfo;
-
     this.type = 'BlockStatement';
-    this.sexpr = sexpr;
+
+    this.path = path;
+    this.params = params || [];
+    this.hash = hash;
     this.program  = program;
     this.inverse  = inverse;
 
@@ -31,12 +35,15 @@ var AST = {
     this.closeStrip = closeStrip;
   },
 
-  PartialStatement: function(sexpr, strip, locInfo) {
+  PartialStatement: function(name, params, hash, strip, locInfo) {
     this.loc = locInfo;
     this.type = 'PartialStatement';
-    this.sexpr = sexpr;
-    this.indent = '';
 
+    this.name = name;
+    this.params = params || [];
+    this.hash = hash;
+
+    this.indent = '';
     this.strip = strip;
   },
 
@@ -112,8 +119,8 @@ var AST = {
     // * it is an eligible helper, and
     // * it has at least one parameter or hash segment
     // TODO: Make these public utility methods
-    helperExpression: function(sexpr) {
-      return !!(sexpr.isHelper || sexpr.params.length || sexpr.hash);
+    helperExpression: function(node) {
+      return !!(node.type === 'SubExpression' || node.params.length || node.hash);
     },
 
     scopedId: function(path) {

lib/handlebars/compiler/compiler.js

@@ -110,28 +110,27 @@ Compiler.prototype = {
   },
 
   BlockStatement: function(block) {
-    var sexpr = block.sexpr,
-        program = block.program,
+    var program = block.program,
         inverse = block.inverse;
 
     program = program && this.compileProgram(program);
     inverse = inverse && this.compileProgram(inverse);
 
-    var type = this.classifySexpr(sexpr);
+    var type = this.classifySexpr(block);
 
     if (type === 'helper') {
-      this.helperSexpr(sexpr, program, inverse);
+      this.helperSexpr(block, program, inverse);
     } else if (type === 'simple') {
-      this.simpleSexpr(sexpr);
+      this.simpleSexpr(block);
 
       // now that the simple mustache is resolved, we need to
       // evaluate it by executing `blockHelperMissing`
       this.opcode('pushProgram', program);
       this.opcode('pushProgram', inverse);
       this.opcode('emptyHash');
-      this.opcode('blockValue', sexpr.path.original);
+      this.opcode('blockValue', block.path.original);
     } else {
-      this.ambiguousSexpr(sexpr, program, inverse);
+      this.ambiguousSexpr(block, program, inverse);
 
       // now that the simple mustache is resolved, we need to
       // evaluate it by executing `blockHelperMissing`
@@ -145,29 +144,35 @@ Compiler.prototype = {
   },
 
   PartialStatement: function(partial) {
-    var partialName = partial.sexpr.path.original;
     this.usePartial = true;
 
-    var params = partial.sexpr.params;
+    var params = partial.params;
     if (params.length > 1) {
       throw new Exception('Unsupported number of partial arguments: ' + params.length, partial);
     } else if (!params.length) {
       params.push({type: 'PathExpression', parts: [], depth: 0});
     }
 
-    this.setupFullMustacheParams(partial.sexpr, undefined, undefined, true);
+    var partialName = partial.name.original,
+        isDynamic = partial.name.type === 'SubExpression';
+    if (isDynamic) {
+      this.accept(partial.name);
+    }
+
+    this.setupFullMustacheParams(partial, undefined, undefined, true);
 
     var indent = partial.indent || '';
     if (this.options.preventIndent && indent) {
       this.opcode('appendContent', indent);
       indent = '';
     }
-    this.opcode('invokePartial', partialName, indent);
+
+    this.opcode('invokePartial', isDynamic, partialName, indent);
     this.opcode('append');
   },
 
   MustacheStatement: function(mustache) {
-    this.accept(mustache.sexpr);
+    this.SubExpression(mustache);
 
     if(mustache.escaped && !this.options.noEscape) {
       this.opcode('appendEscaped');
@@ -334,11 +339,6 @@ Compiler.prototype = {
   pushParam: function(val) {
     var value = val.value != null ? val.value : val.original || '';
 
-    // Force helper evaluation
-    if (val.type === 'SubExpression') {
-      val.isHelper = true;
-    }
-
     if (this.stringParams) {
       if (value.replace) {
         value = value

lib/handlebars/compiler/helpers.js

@@ -52,39 +52,40 @@ export function preparePath(data, parts, locInfo) {
   return new this.PathExpression(data, depth, dig, original, locInfo);
 }
 
-export function prepareMustache(sexpr, open, strip, locInfo) {
+export function prepareMustache(path, params, hash, open, strip, locInfo) {
   /*jshint -W040 */
   // Must use charAt to support IE pre-10
   var escapeFlag = open.charAt(3) || open.charAt(2),
       escaped = escapeFlag !== '{' && escapeFlag !== '&';
 
-  return new this.MustacheStatement(sexpr, escaped, strip, this.locInfo(locInfo));
+  return new this.MustacheStatement(path, params, hash, escaped, strip, this.locInfo(locInfo));
 }
 
 export function prepareRawBlock(openRawBlock, content, close, locInfo) {
   /*jshint -W040 */
-  if (openRawBlock.sexpr.path.original !== close) {
-    var errorNode = {loc: openRawBlock.sexpr.loc};
+  if (openRawBlock.path.original !== close) {
+    var errorNode = {loc: openRawBlock.path.loc};
 
-    throw new Exception(openRawBlock.sexpr.path.original + " doesn't match " + close, errorNode);
+    throw new Exception(openRawBlock.path.original + " doesn't match " + close, errorNode);
   }
 
   locInfo = this.locInfo(locInfo);
   var program = new this.Program([content], null, {}, locInfo);
 
   return new this.BlockStatement(
-      openRawBlock.sexpr, program, undefined,
+      openRawBlock.path, openRawBlock.params, openRawBlock.hash,
+      program, undefined,
       {}, {}, {},
       locInfo);
 }
 
 export function prepareBlock(openBlock, program, inverseAndProgram, close, inverted, locInfo) {
   /*jshint -W040 */
   // When we are chaining inverse calls, we will not have a close path
-  if (close && close.path && openBlock.sexpr.path.original !== close.path.original) {
-    var errorNode = {loc: openBlock.sexpr.loc};
+  if (close && close.path && openBlock.path.original !== close.path.original) {
+    var errorNode = {loc: openBlock.path.loc};
 
-    throw new Exception(openBlock.sexpr.path.original + ' doesn\'t match ' + close.path.original, errorNode);
+    throw new Exception(openBlock.path.original + ' doesn\'t match ' + close.path.original, errorNode);
   }
 
   program.blockParams = openBlock.blockParams;
@@ -108,7 +109,8 @@ export function prepareBlock(openBlock, program, inverseAndProgram, close, inver
   }
 
   return new this.BlockStatement(
-      openBlock.sexpr, program, inverse,
+      openBlock.path, openBlock.params, openBlock.hash,
+      program, inverse,
       openBlock.strip, inverseStrip, close && close.strip,
       this.locInfo(locInfo));
 }

lib/handlebars/compiler/javascript-compiler.js

@@ -644,17 +644,26 @@ JavaScriptCompiler.prototype = {
   //
   // This operation pops off a context, invokes a partial with that context,
   // and pushes the result of the invocation back.
-  invokePartial: function(name, indent) {
+  invokePartial: function(isDynamic, name, indent) {
     var params = [],
         options = this.setupParams(name, 1, params, false);
 
+    if (isDynamic) {
+      name = this.popStack();
+      delete options.name;
+    }
+
     if (indent) {
       options.indent = JSON.stringify(indent);
     }
     options.helpers = 'helpers';
     options.partials = 'partials';
 
-    params.unshift(this.nameLookup('partials', name, 'partial'));
+    if (!isDynamic) {
+      params.unshift(this.nameLookup('partials', name, 'partial'));
+    } else {
+      params.unshift(name);
+    }
 
     if (this.options.compat) {
       options.depths = 'depths';

lib/handlebars/compiler/printer.js

@@ -45,15 +45,15 @@ PrintVisitor.prototype.Program = function(program) {
 };
 
 PrintVisitor.prototype.MustacheStatement = function(mustache) {
-  return this.pad('{{ ' + this.accept(mustache.sexpr) + ' }}');
+  return this.pad('{{ ' + this.SubExpression(mustache) + ' }}');
 };
 
 PrintVisitor.prototype.BlockStatement = function(block) {
   var out = "";
 
   out = out + this.pad('BLOCK:');
   this.padding++;
-  out = out + this.pad(this.accept(block.sexpr));
+  out = out + this.pad(this.SubExpression(block));
   if (block.program) {
     out = out + this.pad('PROGRAM:');
     this.padding++;
@@ -74,13 +74,12 @@ PrintVisitor.prototype.BlockStatement = function(block) {
 };
 
 PrintVisitor.prototype.PartialStatement = function(partial) {
-  var sexpr = partial.sexpr,
-      content = 'PARTIAL:' + sexpr.path.original;
-  if(sexpr.params[0]) {
-    content += ' ' + this.accept(sexpr.params[0]);
+  var content = 'PARTIAL:' + partial.name.original;
+  if(partial.params[0]) {
+    content += ' ' + this.accept(partial.params[0]);
   }
-  if (sexpr.hash) {
-    content += ' ' + this.accept(sexpr.hash);
+  if (partial.hash) {
+    content += ' ' + this.accept(partial.hash);
   }
   return this.pad('{{> ' + content + ' }}');
 };

lib/handlebars/compiler/visitor.js

@@ -71,17 +71,24 @@ Visitor.prototype = {
   },
 
   MustacheStatement: function(mustache) {
-    this.acceptRequired(mustache, 'sexpr');
+    this.acceptRequired(mustache, 'path');
+    this.acceptArray(mustache.params);
+    this.acceptKey(mustache, 'hash');
   },
 
   BlockStatement: function(block) {
-    this.acceptRequired(block, 'sexpr');
+    this.acceptRequired(block, 'path');
+    this.acceptArray(block.params);
+    this.acceptKey(block, 'hash');
+
     this.acceptKey(block, 'program');
     this.acceptKey(block, 'inverse');
   },
 
   PartialStatement: function(partial) {
-    this.acceptRequired(partial, 'sexpr');
+    this.acceptRequired(partial, 'name');
+    this.acceptArray(partial.params);
+    this.acceptKey(partial, 'hash');
   },
 
   ContentStatement: function(/* content */) {},
@@ -92,6 +99,11 @@ Visitor.prototype = {
     this.acceptArray(sexpr.params);
     this.acceptKey(sexpr, 'hash');
   },
+  PartialExpression: function(partial) {
+    this.acceptRequired(partial, 'name');
+    this.acceptArray(partial.params);
+    this.acceptKey(partial, 'hash');
+  },
 
   PathExpression: function(/* path */) {},