feat(change detection): remove support for "if"

BREAKING CHANGE: Remove if statement support from actions.

Closes #4616

modules/angular2/src/core/change_detection/parser/ast.ts

@@ -1,5 +1,4 @@
-import {isBlank, isPresent, FunctionWrapper} from "angular2/src/core/facade/lang";
-import {Map, ListWrapper, StringMapWrapper} from "angular2/src/core/facade/collection";
+import {ListWrapper} from "angular2/src/core/facade/collection";
 
 export class AST {
   visit(visitor: AstVisitor): any { return null; }
@@ -29,11 +28,6 @@ export class Conditional extends AST {
   visit(visitor: AstVisitor): any { return visitor.visitConditional(this); }
 }
 
-export class If extends AST {
-  constructor(public condition: AST, public trueExp: AST, public falseExp?: AST) { super(); }
-  visit(visitor: AstVisitor): any { return visitor.visitIf(this); }
-}
-
 export class PropertyRead extends AST {
   constructor(public receiver: AST, public name: string, public getter: Function) { super(); }
   visit(visitor: AstVisitor): any { return visitor.visitPropertyRead(this); }
@@ -133,7 +127,6 @@ export interface AstVisitor {
   visitChain(ast: Chain): any;
   visitConditional(ast: Conditional): any;
   visitFunctionCall(ast: FunctionCall): any;
-  visitIf(ast: If): any;
   visitImplicitReceiver(ast: ImplicitReceiver): any;
   visitInterpolation(ast: Interpolation): any;
   visitKeyedRead(ast: KeyedRead): any;
@@ -163,12 +156,6 @@ export class RecursiveAstVisitor implements AstVisitor {
     ast.falseExp.visit(this);
     return null;
   }
-  visitIf(ast: If): any {
-    ast.condition.visit(this);
-    ast.trueExp.visit(this);
-    ast.falseExp.visit(this);
-    return null;
-  }
   visitPipe(ast: BindingPipe): any {
     ast.exp.visit(this);
     this.visitAll(ast.args);
@@ -301,9 +288,4 @@ export class AstTransformer implements AstVisitor {
   }
 
   visitChain(ast: Chain): Chain { return new Chain(this.visitAll(ast.expressions)); }
-
-  visitIf(ast: If): If {
-    let falseExp = isPresent(ast.falseExp) ? ast.falseExp.visit(this) : null;
-    return new If(ast.condition.visit(this), ast.trueExp.visit(this), falseExp);
-  }
 }

modules/angular2/src/core/change_detection/parser/lexer.ts

@@ -56,10 +56,6 @@ export class Token {
 
   isKeywordTrue(): boolean { return (this.type == TokenType.Keyword && this.strValue == "true"); }
 
-  isKeywordIf(): boolean { return (this.type == TokenType.Keyword && this.strValue == "if"); }
-
-  isKeywordElse(): boolean { return (this.type == TokenType.Keyword && this.strValue == "else"); }
-
   isKeywordFalse(): boolean { return (this.type == TokenType.Keyword && this.strValue == "false"); }
 
   toNumber(): number {

modules/angular2/src/core/change_detection/parser/parser.ts

@@ -29,7 +29,6 @@ import {
   Binary,
   PrefixNot,
   Conditional,
-  If,
   BindingPipe,
   Chain,
   KeyedRead,
@@ -429,19 +428,6 @@ export class _ParseAST {
       this.advance();
       return new LiteralPrimitive(false);
 
-    } else if (this.parseAction && this.next.isKeywordIf()) {
-      this.advance();
-      this.expectCharacter($LPAREN);
-      let condition = this.parseExpression();
-      this.expectCharacter($RPAREN);
-      let ifExp = this.parseExpressionOrBlock();
-      let elseExp;
-      if (this.next.isKeywordElse()) {
-        this.advance();
-        elseExp = this.parseExpressionOrBlock();
-      }
-      return new If(condition, ifExp, elseExp);
-
     } else if (this.optionalCharacter($LBRACKET)) {
       var elements = this.parseExpressionList($RBRACKET);
       this.expectCharacter($RBRACKET);
@@ -542,16 +528,6 @@ export class _ParseAST {
     return positionals;
   }
 
-  parseExpressionOrBlock(): AST {
-    if (this.optionalCharacter($LBRACE)) {
-      let block = this.parseBlockContent();
-      this.expectCharacter($RBRACE);
-      return block;
-    }
-
-    return this.parseExpression();
-  }
-
   parseBlockContent(): AST {
     if (!this.parseAction) {
       this.error("Binding expression cannot contain chained expression");
@@ -688,6 +664,4 @@ class SimpleExpressionChecker implements AstVisitor {
   }
 
   visitChain(ast: Chain) { this.simple = false; }
-
-  visitIf(ast: If) { this.simple = false; }
 }

modules/angular2/src/core/change_detection/proto_change_detector.ts

@@ -12,7 +12,6 @@ import {
   Binary,
   Chain,
   Conditional,
-  If,
   BindingPipe,
   FunctionCall,
   ImplicitReceiver,
@@ -266,8 +265,6 @@ class _ConvertAstIntoProtoRecords implements AstVisitor {
     return this._addRecord(RecordType.Chain, "chain", null, args, null, 0);
   }
 
-  visitIf(ast: If) { throw new BaseException('Not supported'); }
-
   _visitAll(asts: any[]) {
     var res = ListWrapper.createFixedSize(asts.length);
     for (var i = 0; i < asts.length; ++i) {

modules/angular2/test/core/change_detection/parser/parser_spec.ts

@@ -173,13 +173,6 @@ export function main() {
         });
       });
 
-      describe("if", () => {
-        it('should parse if statements', () => {
-          checkAction("if (true) a = 0");
-          checkAction("if (true) {a = 0;}", "if (true) a = 0");
-        });
-      });
-
       describe("assignment", () => {
         it("should support field assignments", () => {
           checkAction("a = 12");

modules/angular2/test/core/change_detection/parser/unparser.ts

@@ -7,7 +7,6 @@ import {
   Chain,
   Conditional,
   EmptyExpr,
-  If,
   BindingPipe,
   FunctionCall,
   ImplicitReceiver,
@@ -70,17 +69,6 @@ export class Unparser implements AstVisitor {
     this._visit(ast.falseExp);
   }
 
-  visitIf(ast: If) {
-    this._expression += 'if (';
-    this._visit(ast.condition);
-    this._expression += ') ';
-    this._visitExpOrBlock(ast.trueExp);
-    if (isPresent(ast.falseExp)) {
-      this._expression += ' else ';
-      this._visitExpOrBlock(ast.falseExp);
-    }
-  }
-
   visitPipe(ast: BindingPipe) {
     this._expression += '(';
     this._visit(ast.exp);
@@ -200,11 +188,4 @@ export class Unparser implements AstVisitor {
   }
 
   private _visit(ast: AST) { ast.visit(this); }
-
-  private _visitExpOrBlock(ast: AST) {
-    var isBlock = ast instanceof Chain || ast instanceof EmptyExpr;
-    if (isBlock) this._expression += '{ ';
-    this._visit(ast);
-    if (isBlock) this._expression += ' }';
-  }
 }