feat(Parser): implement Parser

Add a simple parser implementation that supports only field reads.

modules/change_detection/src/parser/ast.js

@@ -0,0 +1,39 @@
+export class AST {
+  eval(context) {
+  }
+
+  visit(visitor) {
+  }
+}
+
+export class ImplicitReceiver extends AST {
+  eval(context) {
+    return context;
+  }
+
+  visit(visitor) {
+    visitor.visitImplicitReceiver(this);
+  }
+}
+
+export class FieldRead extends AST {
+  constructor(receiver:AST, name:string, getter:Function) {
+    this.receiver = receiver;
+    this.name = name;
+    this.getter = getter;
+  }
+
+  eval(context) {
+    return this.getter(this.receiver.eval(context));
+  }
+
+  visit(visitor) {
+    visitor.visitFieldRead(this);
+  }
+}
+
+//INTERFACE
+export class AstVisitor {
+  visitImplicitReceiver(ast:ImplicitReceiver) {}
+  visitFieldRead(ast:FieldRead) {}
+}

modules/change_detection/src/parser/closure_map.dart

@@ -0,0 +1,8 @@
+import 'dart:mirrors';
+
+class ClosureMap {
+  Function getter(String name) {
+    var symbol = new Symbol(name);
+    return (receiver) => reflect(receiver).getField(symbol).reflectee;
+  }
+}

modules/change_detection/src/parser/closure_map.es6

@@ -0,0 +1,5 @@
+export class ClosureMap {
+  getter(name:string) {
+    return new Function('o', 'return o.' + name + ';');
+  }
+}

modules/change_detection/src/parser/lexer.js

@@ -1,13 +1,25 @@
 import {List, ListWrapper, SetWrapper} from "facade/collection";
 import {int, FIELD, NumberWrapper, StringJoiner, StringWrapper} from "facade/lang";
 
-// TODO(chirayu): Rewrite as consts when possible.
-export var TOKEN_TYPE_CHARACTER  = 1;
-export var TOKEN_TYPE_IDENTIFIER = 2;
-export var TOKEN_TYPE_KEYWORD    = 3;
-export var TOKEN_TYPE_STRING     = 4;
-export var TOKEN_TYPE_OPERATOR   = 5;
-export var TOKEN_TYPE_NUMBER     = 6;
+export const TOKEN_TYPE_CHARACTER  = 1;
+export const TOKEN_TYPE_IDENTIFIER = 2;
+export const TOKEN_TYPE_KEYWORD    = 3;
+export const TOKEN_TYPE_STRING     = 4;
+export const TOKEN_TYPE_OPERATOR   = 5;
+export const TOKEN_TYPE_NUMBER     = 6;
+
+export class Lexer {
+  tokenize(text:string):List {
+    var scanner = new _Scanner(text);
+    var tokens = [];
+    var token = scanner.scanToken();
+    while (token != null) {
+      ListWrapper.push(tokens, token);
+      token = scanner.scanToken();
+    }
+    return tokens;
+  }
+}
 
 export class Token {
   @FIELD('final index:int')
@@ -107,35 +119,35 @@ function newNumberToken(index:int, n:number):Token {
 }
 
 
-var EOF:Token = new Token(-1, 0, 0, "");
+export var EOF:Token = new Token(-1, 0, 0, "");
 
-const $EOF       = 0;
-const $TAB       = 9;
-const $LF        = 10;
-const $VTAB      = 11;
-const $FF        = 12;
-const $CR        = 13;
-const $SPACE     = 32;
-const $BANG      = 33;
-const $DQ        = 34;
-const $$         = 36;
-const $PERCENT   = 37;
-const $AMPERSAND = 38;
-const $SQ        = 39;
-const $LPAREN    = 40;
-const $RPAREN    = 41;
-const $STAR      = 42;
-const $PLUS      = 43;
-const $COMMA     = 44;
-const $MINUS     = 45;
-const $PERIOD    = 46;
-const $SLASH     = 47;
-const $COLON     = 58;
-const $SEMICOLON = 59;
-const $LT        = 60;
-const $EQ        = 61;
-const $GT        = 62;
-const $QUESTION  = 63;
+export const $EOF       = 0;
+export const $TAB       = 9;
+export const $LF        = 10;
+export const $VTAB      = 11;
+export const $FF        = 12;
+export const $CR        = 13;
+export const $SPACE     = 32;
+export const $BANG      = 33;
+export const $DQ        = 34;
+export const $$         = 36;
+export const $PERCENT   = 37;
+export const $AMPERSAND = 38;
+export const $SQ        = 39;
+export const $LPAREN    = 40;
+export const $RPAREN    = 41;
+export const $STAR      = 42;
+export const $PLUS      = 43;
+export const $COMMA     = 44;
+export const $MINUS     = 45;
+export const $PERIOD    = 46;
+export const $SLASH     = 47;
+export const $COLON     = 58;
+export const $SEMICOLON = 59;
+export const $LT        = 60;
+export const $EQ        = 61;
+export const $GT        = 62;
+export const $QUESTION  = 63;
 
 const $0 = 48;
 const $9 = 57;
@@ -173,7 +185,7 @@ export class ScannerError extends Error {
   }
 }
 
-export class Scanner {
+class _Scanner {
   @FIELD('final input:String')
   @FIELD('final length:int')
   @FIELD('peek:int')
@@ -191,7 +203,6 @@ export class Scanner {
     this.peek = ++this.index >= this.length ? $EOF : StringWrapper.charCodeAt(this.input, this.index);
   }
 
-
   scanToken():Token {
     var input = this.input,
         length = this.length,

modules/change_detection/src/parser/parser.js

@@ -1,2 +1,81 @@
+import {FIELD, int} from 'facade/lang';
+import {ListWrapper, List} from 'facade/collection';
+import {Lexer, EOF, Token, $PERIOD} from './lexer';
+import {ClosureMap} from './closure_map';
+import {AST, ImplicitReceiver, FieldRead} from './ast';
+
+var _implicitReceiver = new ImplicitReceiver();
+
 export class Parser {
+  @FIELD('final _lexer:Lexer')
+  @FIELD('final _closureMap:ClosureMap')
+  constructor(lexer:Lexer, closureMap:ClosureMap){
+    this._lexer = lexer;
+    this._closureMap = closureMap;
+  }
+
+  parse(input:string):AST {
+    var tokens = this._lexer.tokenize(input);
+    return new _ParseAST(tokens, this._closureMap).parseChain();
+  }
 }
+
+class _ParseAST {
+  @FIELD('final tokens:List<Token>')
+  @FIELD('final closureMap:ClosureMap')
+  @FIELD('index:int')
+  constructor(tokens:List, closureMap:ClosureMap) {
+    this.tokens = tokens;
+    this.index = 0;
+    this.closureMap = closureMap;
+  }
+
+  peek(offset:int):Token {
+    var i = this.index + offset;
+    return i < this.tokens.length ? this.tokens[i] : EOF;
+  }
+
+  get next():Token {
+    return this.peek(0);
+  }
+
+  advance() {
+    this.index ++;
+  }
+
+  optionalCharacter(code:int):boolean {
+    if (this.next.isCharacter(code)) {
+      this.advance();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  parseChain():AST {
+    var exprs = [];
+    while (this.index < this.tokens.length) {
+      ListWrapper.push(exprs, this.parseAccess());
+    }
+    return ListWrapper.first(exprs);
+  }
+
+  parseAccess():AST {
+    var result = this.parseFieldRead(_implicitReceiver);
+    while(this.optionalCharacter($PERIOD)) {
+      result = this.parseFieldRead(result);
+    }
+    return result;
+  }
+
+  parseFieldRead(receiver):AST {
+    var id = this.parseIdentifier();
+    return new FieldRead(receiver, id, this.closureMap.getter(id));
+  }
+
+  parseIdentifier():string {
+    var n = this.next;
+    this.advance();
+    return n.toString();
+  }
+}

modules/change_detection/src/watch_group.js

@@ -1,45 +1,42 @@
 import {ProtoRecord, Record} from './record';
-import {FIELD} from 'facade/lang';
-import {ListWrapper} from 'facade/collection';
+import {FIELD, IMPLEMENTS, isBlank, isPresent} from 'facade/lang';
+import {AST, FieldRead, ImplicitReceiver, AstVisitor} from './parser/ast';
 
 export class ProtoWatchGroup {
-  @FIELD('final headRecord:ProtoRecord')
-  @FIELD('final tailRecord:ProtoRecord')
+  @FIELD('headRecord:ProtoRecord')
+  @FIELD('tailRecord:ProtoRecord')
   constructor() {
     this.headRecord = null;
     this.tailRecord = null;
   }
 
   /**
-   * Parses [expression] into [ProtoRecord]s and adds them to [ProtoWatchGroup].
+   * Parses [ast] into [ProtoRecord]s and adds them to [ProtoWatchGroup].
    *
-   * @param expression The expression to watch
+   * @param ast The expression to watch
    * @param memento an opaque object which will be passed to WatchGroupDispatcher on
    *        detecting a change.
    * @param shallow Should collections be shallow watched
    */
-  watch(expression:string,
+  watch(ast:AST,
         memento,
         shallow = false)
   {
-    var parts = expression.split('.');
-    var protoRecords = ListWrapper.createFixedSize(parts.length);
+    var creator = new ProtoRecordCreator(this);
+    creator.createRecordsFromAST(ast, memento);
+    this._addRecords(creator.headRecord, creator.tailRecord);
+  }
 
-    for (var i = parts.length - 1; i >= 0; i--) {
-      protoRecords[i] = new ProtoRecord(this, parts[i], memento);
-      memento = null;
-    }
-
-    for (var i = 0; i < parts.length; i++) {
-      var protoRecord = protoRecords[i];
-      if (this.headRecord === null) {
-        this.headRecord = this.tailRecord = protoRecord;
-      } else {
-        this.tailRecord.next = protoRecord;
-        protoRecord.prev = this.tailRecord;
-        this.tailRecord = protoRecord;
-      }
+  // try to encapsulate this behavior in some class (e.g., LinkedList)
+  // so we can say: group.appendList(creator.list);
+  _addRecords(head:ProtoRecord, tail:ProtoRecord) {
+    if (isBlank(this.headRecord)) {
+      this.headRecord = head;
+    } else {
+      this.tailRecord.next = head;
+      head.prev = this.tailRecord;
     }
+    this.tailRecord = tail;
   }
 
   instantiate(dispatcher:WatchGroupDispatcher):WatchGroup {
@@ -109,3 +106,41 @@ export class WatchGroupDispatcher {
   // The record holds the previous value at the time of the call
   onRecordChange(record:Record, context) {}
 }
+
+@IMPLEMENTS(AstVisitor)
+class ProtoRecordCreator {
+  @FIELD('final protoWatchGroup:ProtoWatchGroup')
+  @FIELD('headRecord:ProtoRecord')
+  @FIELD('tailRecord:ProtoRecord')
+  constructor(protoWatchGroup) {
+    this.protoWatchGroup = protoWatchGroup;
+    this.headRecord = null;
+    this.tailRecord = null;
+  }
+
+  visitImplicitReceiver(ast:ImplicitReceiver) {
+    //do nothing
+  }
+
+  visitFieldRead(ast:FieldRead) {
+    ast.receiver.visit(this);
+    this.add(new ProtoRecord(this.protoWatchGroup, ast.name, null));
+  }
+
+  createRecordsFromAST(ast:AST, memento){
+    ast.visit(this);
+    if (isPresent(this.tailRecord)) {
+      this.tailRecord.dispatchMemento = memento;
+    }
+  }
+
+  add(protoRecord:ProtoRecord) {
+    if (this.headRecord === null) {
+      this.headRecord = this.tailRecord = protoRecord;
+    } else {
+      this.tailRecord.next = protoRecord;
+      protoRecord.prev = this.tailRecord;
+      this.tailRecord = protoRecord;
+    }
+  }
+}

modules/change_detection/test/change_detector_spec.js

@@ -1,33 +1,47 @@
 import {describe, it, xit, expect} from 'test_lib/test_lib';
 
 import {List, ListWrapper} from 'facade/collection';
+import {ImplicitReceiver, FieldRead} from 'change_detection/parser/ast';
+import {ClosureMap} from 'change_detection/parser/closure_map';
 
 import {
   ChangeDetector,
   ProtoWatchGroup,
   WatchGroup,
-  WatchGroupDispatcher
+  WatchGroupDispatcher,
+  ProtoRecord
 } from 'change_detection/change_detector';
 
 import {Record} from 'change_detection/record';
 
 export function main() {
+  function ast(exp:string) {
+    var parts = exp.split(".");
+    var cm = new ClosureMap();
+    return ListWrapper.reduce(parts, function (ast, fieldName) {
+      return new FieldRead(ast, fieldName, cm.getter(fieldName));
+    }, new ImplicitReceiver());
+  }
+
   describe('change_detection', function() {
     describe('ChangeDetection', function() {
       it('should do simple watching', function() {
         var person = new Person('misko', 38);
         var pwg = new ProtoWatchGroup();
-        pwg.watch('name', 'name');
-        pwg.watch('age', 'age');
+        pwg.watch(ast('name'), 'name');
+        pwg.watch(ast('age'), 'age');
         var dispatcher = new LoggingDispatcher();
         var wg = pwg.instantiate(dispatcher);
         wg.setContext(person);
+
         var cd = new ChangeDetector(wg);
         cd.detectChanges();
         expect(dispatcher.log).toEqual(['name=misko', 'age=38']);
+
         dispatcher.clear();
         cd.detectChanges();
         expect(dispatcher.log).toEqual([]);
+
         person.age = 1;
         person.name = "Misko";
         cd.detectChanges();
@@ -38,16 +52,19 @@ export function main() {
         var address = new Address('Grenoble');
         var person = new Person('Victor', 36, address);
         var pwg = new ProtoWatchGroup();
-        pwg.watch('address.city', 'address.city', false);
+        pwg.watch(ast('address.city'), 'address.city', false);
         var dispatcher = new LoggingDispatcher();
         var wg = pwg.instantiate(dispatcher);
         wg.setContext(person);
+
         var cd = new ChangeDetector(wg);
         cd.detectChanges();
         expect(dispatcher.log).toEqual(['address.city=Grenoble']);
+
         dispatcher.clear();
         cd.detectChanges();
         expect(dispatcher.log).toEqual([]);
+
         address.city = 'Mountain View';
         cd.detectChanges();
         expect(dispatcher.log).toEqual(['address.city=Mountain View']);

modules/change_detection/test/parser/lexer_spec.js

@@ -1,17 +1,10 @@
 import {describe, it, expect} from 'test_lib/test_lib';
-import {Scanner, Token} from 'change_detection/parser/scanner';
+import {Lexer, Token} from 'change_detection/parser/lexer';
 import {List, ListWrapper} from "facade/collection";
 import {StringWrapper, int} from "facade/lang";
 
 function lex(text:string):List {
-  var scanner:Scanner = new Scanner(text);
-  var tokens:List<Token> = [];
-  var token:Token = scanner.scanToken();
-  while (token != null) {
-    ListWrapper.push(tokens, token);
-    token = scanner.scanToken();
-  }
-  return tokens;
+  return new Lexer().tokenize(text);
 }
 
 function expectToken(token, index) {
@@ -56,7 +49,7 @@ function expectKeywordToken(token, index, keyword) {
 
 
 export function main() {
-  describe('scanner', function() {
+  describe('lexer', function() {
     describe('token', function() {
       it('should tokenize a simple identifier', function() {
         var tokens:List<int> = lex("j");

modules/change_detection/test/parser/parser_spec.js

@@ -0,0 +1,38 @@
+import {ddescribe, describe, it, expect, beforeEach} from 'test_lib/test_lib';
+import {Parser} from 'change_detection/parser/parser';
+import {Lexer} from 'change_detection/parser/lexer';
+import {ClosureMap} from 'change_detection/parser/closure_map';
+
+class TestData {
+  constructor(a) {
+    this.a = a;
+  }
+}
+
+export function main() {
+  function td({a}) {
+    return new TestData(a);
+  }
+
+  describe("parser", () => {
+    describe("field access", () => {
+      var parser;
+
+      beforeEach(() => {
+        parser = new Parser(new Lexer(), new ClosureMap());
+      });
+
+      it("should parse field access",() => {
+        var exp = parser.parse("a");
+        var context = td({a: 999});
+        expect(exp.eval(context)).toEqual(999);
+      });
+
+      it("should parse nested field access",() => {
+        var exp = parser.parse("a.a");
+        var context = td({a: td({a: 999})});
+        expect(exp.eval(context)).toEqual(999);
+      });
+    });
+  });
+}

modules/facade/src/collection.dart

@@ -39,6 +39,9 @@ class ListWrapper {
   static forEach(list, fn) {
     list.forEach(fn);
   }
+  static reduce(List list, Function fn, init) {
+    return list.fold(init, fn);
+  }
   static first(List list) => list.first;
   static last(List list) => list.last;
   static List reversed(List list) => list.reversed.toList();

modules/facade/src/collection.es6

@@ -60,6 +60,9 @@ export class ListWrapper {
     }
     return null;
   }
+  static reduce(list:List, fn:Function, init) {
+    return list.reduce(fn, init);
+}
   static filter(array, pred:Function) {
     return array.filter(pred);
   }