| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| // @dart = 2.9 |
| |
| // ignore_for_file: always_declare_return_types, prefer_single_quotes |
| // ignore_for_file: prefer_collection_literals, omit_local_variable_types |
| // ignore_for_file: prefer_final_fields |
| // ignore_for_file: prefer_initializing_formals |
| // ignore_for_file: slash_for_doc_comments, unnecessary_const |
| // ignore_for_file: use_function_type_syntax_for_parameters |
| |
| part of js_ast; |
| |
| class JavaScriptPrintingOptions { |
| final bool shouldCompressOutput; |
| final bool minifyLocalVariables; |
| final bool preferSemicolonToNewlineInMinifiedOutput; |
| final bool allowSingleLineIfStatements; |
| |
| /// True to allow keywords in properties, such as `obj.var` or `obj.function` |
| /// Modern JS engines support this. |
| final bool allowKeywordsInProperties; |
| |
| JavaScriptPrintingOptions( |
| {this.shouldCompressOutput = false, |
| this.minifyLocalVariables = false, |
| this.preferSemicolonToNewlineInMinifiedOutput = false, |
| this.allowKeywordsInProperties = false, |
| this.allowSingleLineIfStatements = false}); |
| } |
| |
| /// An environment in which JavaScript printing is done. Provides emitting of |
| /// text and pre- and post-visit callbacks. |
| abstract class JavaScriptPrintingContext { |
| /// Signals an error. This should happen only for serious internal errors. |
| void error(String message) { |
| throw message; |
| } |
| |
| /// Adds [string] to the output. |
| void emit(String string); |
| |
| /// Callback immediately before printing [node]. Whitespace may be printed |
| /// after this callback before the first non-whitespace character for [node]. |
| void enterNode(Node node) {} |
| |
| /// Callback after printing the last character representing [node]. |
| void exitNode(Node node) {} |
| |
| Printer printer; |
| } |
| |
| /// A simple implementation of [JavaScriptPrintingContext] suitable for tests. |
| class SimpleJavaScriptPrintingContext extends JavaScriptPrintingContext { |
| final StringBuffer buffer = StringBuffer(); |
| |
| @override |
| void emit(String string) { |
| buffer.write(string); |
| } |
| |
| String getText() => buffer.toString(); |
| } |
| |
| // TODO(ochafik): Inline the body of [TypeScriptTypePrinter] here if/when it no |
| // longer needs to share utils with [ClosureTypePrinter]. |
| class Printer implements NodeVisitor { |
| final JavaScriptPrintingOptions options; |
| final JavaScriptPrintingContext context; |
| final bool shouldCompressOutput; |
| final DanglingElseVisitor danglingElseVisitor; |
| final LocalNamer localNamer; |
| |
| bool inForInit = false; |
| bool atStatementBegin = false; |
| bool inNewTarget = false; |
| bool pendingSemicolon = false; |
| bool pendingSpace = false; |
| |
| // The current indentation level. |
| int _indentLevel = 0; |
| // A cache of all indentation strings used so far. |
| List<String> _indentList = <String>[""]; |
| |
| /// Whether the next call to [indent] should just be a no-op. |
| bool _skipNextIndent = false; |
| |
| static final identifierCharacterRegExp = RegExp(r'^[a-zA-Z_0-9$]'); |
| static final expressionContinuationRegExp = RegExp(r'^[-+([]'); |
| |
| Printer(JavaScriptPrintingOptions options, JavaScriptPrintingContext context, |
| {LocalNamer localNamer}) |
| : options = options, |
| context = context, |
| shouldCompressOutput = options.shouldCompressOutput, |
| danglingElseVisitor = DanglingElseVisitor(context), |
| localNamer = determineRenamer(localNamer, options) { |
| context.printer = this; |
| } |
| |
| static LocalNamer determineRenamer( |
| LocalNamer localNamer, JavaScriptPrintingOptions options) { |
| if (localNamer != null) return localNamer; |
| return (options.shouldCompressOutput && options.minifyLocalVariables) |
| ? MinifyRenamer() |
| : IdentityNamer(); |
| } |
| |
| // The current indentation string. |
| String get indentation { |
| // Lazily add new indentation strings as required. |
| while (_indentList.length <= _indentLevel) { |
| _indentList.add(_indentList.last + " "); |
| } |
| return _indentList[_indentLevel]; |
| } |
| |
| void indentMore() { |
| _indentLevel++; |
| } |
| |
| void indentLess() { |
| _indentLevel--; |
| } |
| |
| /// Always emit a newline, even under `enableMinification`. |
| void forceLine() { |
| out("\n"); |
| } |
| |
| /// Emits a newline for readability. |
| void lineOut() { |
| if (!shouldCompressOutput) forceLine(); |
| } |
| |
| void spaceOut() { |
| if (!shouldCompressOutput) out(" "); |
| } |
| |
| String lastAddedString; |
| int get lastCharCode { |
| if (lastAddedString == null) return 0; |
| assert(lastAddedString.isNotEmpty); |
| return lastAddedString.codeUnitAt(lastAddedString.length - 1); |
| } |
| |
| void out(String str) { |
| if (str != "") { |
| if (pendingSemicolon) { |
| if (!shouldCompressOutput) { |
| context.emit(";"); |
| } else if (str != "}") { |
| // We want to output newline instead of semicolon because it makes |
| // the raw stack traces much easier to read and it also makes line- |
| // based tools like diff work much better. JavaScript will |
| // automatically insert the semicolon at the newline if it means a |
| // parsing error is avoided, so we can only do this trick if the |
| // next line is not something that can be glued onto a valid |
| // expression to make a new valid expression. |
| |
| // If we're using the new emitter where most pretty printed code |
| // is escaped in strings, it is a lot easier to deal with semicolons |
| // than newlines because the former doesn't need escaping. |
| if (options.preferSemicolonToNewlineInMinifiedOutput || |
| expressionContinuationRegExp.hasMatch(str)) { |
| context.emit(";"); |
| } else { |
| context.emit("\n"); |
| } |
| } |
| } |
| if (pendingSpace && |
| (!shouldCompressOutput || identifierCharacterRegExp.hasMatch(str))) { |
| context.emit(" "); |
| } |
| pendingSpace = false; |
| pendingSemicolon = false; |
| context.emit(str); |
| lastAddedString = str; |
| } |
| } |
| |
| void outLn(String str) { |
| out(str); |
| lineOut(); |
| } |
| |
| void outSemicolonLn() { |
| if (shouldCompressOutput) { |
| pendingSemicolon = true; |
| } else { |
| out(";"); |
| forceLine(); |
| } |
| } |
| |
| void outIndent(String str) { |
| indent(); |
| out(str); |
| } |
| |
| void outIndentLn(String str) { |
| indent(); |
| outLn(str); |
| } |
| |
| void skipNextIndent() { |
| _skipNextIndent = true; |
| } |
| |
| void indent() { |
| if (_skipNextIndent) { |
| _skipNextIndent = false; |
| return; |
| } |
| if (!shouldCompressOutput) { |
| out(indentation); |
| } |
| } |
| |
| visit(Node node) { |
| context.enterNode(node); |
| node.accept(this); |
| context.exitNode(node); |
| } |
| |
| visitCommaSeparated(List<Expression> nodes, int hasRequiredType, |
| {bool newInForInit, bool newAtStatementBegin}) { |
| for (int i = 0; i < nodes.length; i++) { |
| if (i != 0) { |
| atStatementBegin = false; |
| out(","); |
| spaceOut(); |
| } |
| visitNestedExpression(nodes[i], hasRequiredType, |
| newInForInit: newInForInit, newAtStatementBegin: newAtStatementBegin); |
| } |
| } |
| |
| visitAll(List<Node> nodes) { |
| nodes.forEach(visit); |
| } |
| |
| @override |
| visitProgram(Program program) { |
| if (program.scriptTag != null) { |
| out('#!${program.scriptTag}\n'); |
| } |
| visitAll(program.body); |
| } |
| |
| bool blockBody(Node body, {bool needsSeparation, bool needsNewline}) { |
| if (body is Block) { |
| spaceOut(); |
| blockOut(body, false, needsNewline); |
| return true; |
| } |
| if (shouldCompressOutput && needsSeparation) { |
| // If [shouldCompressOutput] is false, then the 'lineOut' will insert |
| // the separation. |
| out(" "); |
| } else { |
| lineOut(); |
| } |
| indentMore(); |
| visit(body); |
| indentLess(); |
| return false; |
| } |
| |
| void blockOutWithoutBraces(Node node) { |
| if (node is Block && !node.isScope) { |
| context.enterNode(node); |
| Block block = node; |
| block.statements.forEach(blockOutWithoutBraces); |
| context.exitNode(node); |
| } else { |
| visit(node); |
| } |
| } |
| |
| void blockOut(Block node, bool shouldIndent, bool needsNewline) { |
| if (shouldIndent) indent(); |
| context.enterNode(node); |
| out("{"); |
| lineOut(); |
| indentMore(); |
| node.statements.forEach(blockOutWithoutBraces); |
| indentLess(); |
| indent(); |
| out("}"); |
| context.exitNode(node); |
| if (needsNewline) lineOut(); |
| } |
| |
| @override |
| visitBlock(Block block) { |
| blockOut(block, true, true); |
| } |
| |
| @override |
| visitDebuggerStatement(node) { |
| outIndentLn('debugger;'); |
| } |
| |
| @override |
| visitExpressionStatement(ExpressionStatement expressionStatement) { |
| indent(); |
| visitNestedExpression(expressionStatement.expression, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: true); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitEmptyStatement(EmptyStatement nop) { |
| outIndentLn(";"); |
| } |
| |
| void ifOut(If node, bool shouldIndent) { |
| var then = node.then; |
| var elsePart = node.otherwise; |
| bool hasElse = node.hasElse; |
| |
| // Handle dangling elses and a work-around for Android 4.0 stock browser. |
| // Android 4.0 requires braces for a single do-while in the `then` branch. |
| // See issue 10923. |
| if (hasElse) { |
| bool needsBraces = node.then.accept(danglingElseVisitor) || then is Do; |
| if (needsBraces) { |
| then = Block(<Statement>[then]); |
| } |
| } |
| if (shouldIndent) indent(); |
| out("if"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(node.condition, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| bool thenWasBlock; |
| if (options.allowSingleLineIfStatements && !hasElse && then is! Block) { |
| thenWasBlock = false; |
| spaceOut(); |
| skipNextIndent(); |
| visit(then); |
| } else { |
| thenWasBlock = |
| blockBody(then, needsSeparation: false, needsNewline: !hasElse); |
| } |
| if (hasElse) { |
| if (thenWasBlock) { |
| spaceOut(); |
| } else { |
| indent(); |
| } |
| out("else"); |
| if (elsePart is If) { |
| pendingSpace = true; |
| context.enterNode(elsePart); |
| ifOut(elsePart, false); |
| context.exitNode(elsePart); |
| } else { |
| blockBody(elsePart, needsSeparation: true, needsNewline: true); |
| } |
| } |
| } |
| |
| @override |
| visitIf(If node) { |
| ifOut(node, true); |
| } |
| |
| @override |
| visitFor(For loop) { |
| outIndent("for"); |
| spaceOut(); |
| out("("); |
| if (loop.init != null) { |
| visitNestedExpression(loop.init, EXPRESSION, |
| newInForInit: true, newAtStatementBegin: false); |
| } |
| out(";"); |
| if (loop.condition != null) { |
| spaceOut(); |
| visitNestedExpression(loop.condition, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| out(";"); |
| if (loop.update != null) { |
| spaceOut(); |
| visitNestedExpression(loop.update, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| out(")"); |
| blockBody(loop.body, needsSeparation: false, needsNewline: true); |
| } |
| |
| @override |
| visitForIn(ForIn loop) { |
| outIndent("for"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(loop.leftHandSide, EXPRESSION, |
| newInForInit: true, newAtStatementBegin: false); |
| out(" in"); |
| pendingSpace = true; |
| visitNestedExpression(loop.object, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| blockBody(loop.body, needsSeparation: false, needsNewline: true); |
| } |
| |
| @override |
| visitForOf(ForOf loop) { |
| outIndent("for"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(loop.leftHandSide, EXPRESSION, |
| newInForInit: true, newAtStatementBegin: false); |
| out(" of"); |
| pendingSpace = true; |
| visitNestedExpression(loop.iterable, ASSIGNMENT, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| blockBody(loop.body, needsSeparation: false, needsNewline: true); |
| } |
| |
| @override |
| visitWhile(While loop) { |
| outIndent("while"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(loop.condition, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| blockBody(loop.body, needsSeparation: false, needsNewline: true); |
| } |
| |
| @override |
| visitDo(Do loop) { |
| outIndent("do"); |
| if (blockBody(loop.body, needsSeparation: true, needsNewline: false)) { |
| spaceOut(); |
| } else { |
| indent(); |
| } |
| out("while"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(loop.condition, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitContinue(Continue node) { |
| if (node.targetLabel == null) { |
| outIndent("continue"); |
| } else { |
| outIndent("continue ${node.targetLabel}"); |
| } |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitBreak(Break node) { |
| if (node.targetLabel == null) { |
| outIndent("break"); |
| } else { |
| outIndent("break ${node.targetLabel}"); |
| } |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitReturn(Return node) { |
| if (node.value == null) { |
| outIndent("return"); |
| } else { |
| outIndent("return"); |
| pendingSpace = true; |
| visitNestedExpression(node.value, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitDartYield(DartYield node) { |
| if (node.hasStar) { |
| outIndent("yield*"); |
| } else { |
| outIndent("yield"); |
| } |
| pendingSpace = true; |
| visitNestedExpression(node.expression, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitThrow(Throw node) { |
| outIndent("throw"); |
| pendingSpace = true; |
| visitNestedExpression(node.expression, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitTry(Try node) { |
| outIndent("try"); |
| blockBody(node.body, needsSeparation: true, needsNewline: false); |
| if (node.catchPart != null) { |
| visit(node.catchPart); |
| } |
| if (node.finallyPart != null) { |
| spaceOut(); |
| out("finally"); |
| blockBody(node.finallyPart, needsSeparation: true, needsNewline: true); |
| } else { |
| lineOut(); |
| } |
| } |
| |
| @override |
| visitCatch(Catch node) { |
| spaceOut(); |
| out("catch"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(node.declaration, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| blockBody(node.body, needsSeparation: false, needsNewline: false); |
| } |
| |
| @override |
| visitSwitch(Switch node) { |
| outIndent("switch"); |
| spaceOut(); |
| out("("); |
| visitNestedExpression(node.key, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| spaceOut(); |
| outLn("{"); |
| indentMore(); |
| visitAll(node.cases); |
| indentLess(); |
| outIndentLn("}"); |
| } |
| |
| @override |
| visitSwitchCase(SwitchCase node) { |
| if (node.isDefault) { |
| outIndentLn("default:"); |
| } else { |
| outIndent("case"); |
| pendingSpace = true; |
| visitNestedExpression(node.expression, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| outLn(":"); |
| } |
| if (node.body.statements.isNotEmpty) { |
| blockOut(node.body, true, true); |
| } |
| } |
| |
| @override |
| visitLabeledStatement(LabeledStatement node) { |
| outIndent("${node.label}:"); |
| blockBody(node.body, needsSeparation: false, needsNewline: true); |
| } |
| |
| void functionOut(Fun fun, Identifier name) { |
| out("function"); |
| if (fun.isGenerator) out("*"); |
| if (name != null) { |
| out(" "); |
| // Name must be a [Decl]. Therefore only test for primary expressions. |
| visitNestedExpression(name, PRIMARY, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| localNamer.enterScope(fun); |
| out("("); |
| if (fun.params != null) { |
| visitCommaSeparated(fun.params, PRIMARY, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| out(")"); |
| switch (fun.asyncModifier) { |
| case const AsyncModifier.sync(): |
| break; |
| case const AsyncModifier.async(): |
| out(' async'); |
| break; |
| case const AsyncModifier.syncStar(): |
| out(' sync*'); |
| break; |
| case const AsyncModifier.asyncStar(): |
| out(' async*'); |
| break; |
| } |
| blockBody(fun.body, needsSeparation: false, needsNewline: false); |
| localNamer.leaveScope(); |
| } |
| |
| @override |
| visitFunctionDeclaration(FunctionDeclaration declaration) { |
| indent(); |
| var f = declaration.function; |
| context.enterNode(f); |
| functionOut(f, declaration.name); |
| context.exitNode(f); |
| lineOut(); |
| } |
| |
| visitNestedExpression(Expression node, int requiredPrecedence, |
| {bool newInForInit, bool newAtStatementBegin}) { |
| int nodePrecedence = node.precedenceLevel; |
| bool needsParentheses = |
| // a - (b + c). |
| (requiredPrecedence != EXPRESSION && |
| nodePrecedence < requiredPrecedence) || |
| // for (a = (x in o); ... ; ... ) { ... } |
| (newInForInit && node is Binary && node.op == "in") || |
| // (function() { ... })(). |
| // ({a: 2, b: 3}.toString()). |
| (newAtStatementBegin && |
| (node is NamedFunction || |
| node is FunctionExpression || |
| node is ObjectInitializer)); |
| if (needsParentheses) { |
| inForInit = false; |
| atStatementBegin = false; |
| inNewTarget = false; |
| out("("); |
| visit(node); |
| out(")"); |
| } else { |
| inForInit = newInForInit; |
| atStatementBegin = newAtStatementBegin; |
| visit(node); |
| } |
| } |
| |
| @override |
| visitVariableDeclarationList(VariableDeclarationList list) { |
| // Note: keyword can be null for non-static field declarations. |
| if (list.keyword != null) { |
| out(list.keyword); |
| out(" "); |
| } |
| visitCommaSeparated(list.declarations, ASSIGNMENT, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitArrayBindingPattern(ArrayBindingPattern node) { |
| out("["); |
| visitCommaSeparated(node.variables, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out("]"); |
| } |
| |
| @override |
| visitObjectBindingPattern(ObjectBindingPattern node) { |
| out("{"); |
| visitCommaSeparated(node.variables, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out("}"); |
| } |
| |
| @override |
| visitDestructuredVariable(DestructuredVariable node) { |
| var name = node.name; |
| var property = node.property; |
| if (name != null) { |
| visit(node.name); |
| } else if (property != null) { |
| out("["); |
| visit(node.property); |
| out("]"); |
| } |
| var structure = node.structure; |
| if (structure != null) { |
| if (name != null || property != null) { |
| out(":"); |
| spaceOut(); |
| } |
| visit(structure); |
| } |
| var defaultValue = node.defaultValue; |
| if (defaultValue != null) { |
| spaceOut(); |
| out("="); |
| spaceOut(); |
| visitNestedExpression(defaultValue, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| } |
| |
| @override |
| visitSimpleBindingPattern(SimpleBindingPattern node) { |
| visit(node.name); |
| } |
| |
| @override |
| visitAssignment(Assignment assignment) { |
| visitNestedExpression(assignment.leftHandSide, LEFT_HAND_SIDE, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| if (assignment.value != null) { |
| spaceOut(); |
| String op = assignment.op; |
| if (op != null) out(op); |
| out("="); |
| spaceOut(); |
| visitNestedExpression(assignment.value, ASSIGNMENT, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| } |
| |
| @override |
| visitVariableInitialization(VariableInitialization init) { |
| visitNestedExpression(init.declaration, LEFT_HAND_SIDE, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| if (init.value != null) { |
| spaceOut(); |
| out("="); |
| spaceOut(); |
| visitNestedExpression(init.value, ASSIGNMENT, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| } |
| |
| @override |
| visitConditional(Conditional cond) { |
| visitNestedExpression(cond.condition, LOGICAL_OR, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| spaceOut(); |
| out("?"); |
| spaceOut(); |
| // The then part is allowed to have an 'in'. |
| visitNestedExpression(cond.then, ASSIGNMENT, |
| newInForInit: false, newAtStatementBegin: false); |
| spaceOut(); |
| out(":"); |
| spaceOut(); |
| visitNestedExpression(cond.otherwise, ASSIGNMENT, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitNew(New node) { |
| out("new "); |
| inNewTarget = true; |
| visitNestedExpression(node.target, ACCESS, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| inNewTarget = false; |
| out("("); |
| visitCommaSeparated(node.arguments, SPREAD, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| } |
| |
| @override |
| visitCall(Call call) { |
| visitNestedExpression(call.target, LEFT_HAND_SIDE, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| out("("); |
| visitCommaSeparated(call.arguments, SPREAD, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| } |
| |
| @override |
| visitBinary(Binary binary) { |
| Expression left = binary.left; |
| Expression right = binary.right; |
| String op = binary.op; |
| int leftPrecedenceRequirement; |
| int rightPrecedenceRequirement; |
| bool leftSpace = true; // left<HERE>op right |
| switch (op) { |
| case ',': |
| // x, (y, z) <=> (x, y), z. |
| leftPrecedenceRequirement = EXPRESSION; |
| rightPrecedenceRequirement = EXPRESSION; |
| leftSpace = false; |
| break; |
| case "||": |
| leftPrecedenceRequirement = LOGICAL_OR; |
| // x || (y || z) <=> (x || y) || z. |
| rightPrecedenceRequirement = LOGICAL_OR; |
| break; |
| case "&&": |
| leftPrecedenceRequirement = LOGICAL_AND; |
| // x && (y && z) <=> (x && y) && z. |
| rightPrecedenceRequirement = LOGICAL_AND; |
| break; |
| case "|": |
| leftPrecedenceRequirement = BIT_OR; |
| // x | (y | z) <=> (x | y) | z. |
| rightPrecedenceRequirement = BIT_OR; |
| break; |
| case "^": |
| leftPrecedenceRequirement = BIT_XOR; |
| // x ^ (y ^ z) <=> (x ^ y) ^ z. |
| rightPrecedenceRequirement = BIT_XOR; |
| break; |
| case "&": |
| leftPrecedenceRequirement = BIT_AND; |
| // x & (y & z) <=> (x & y) & z. |
| rightPrecedenceRequirement = BIT_AND; |
| break; |
| case "==": |
| case "!=": |
| case "===": |
| case "!==": |
| leftPrecedenceRequirement = EQUALITY; |
| rightPrecedenceRequirement = RELATIONAL; |
| break; |
| case "<": |
| case ">": |
| case "<=": |
| case ">=": |
| case "instanceof": |
| case "in": |
| leftPrecedenceRequirement = RELATIONAL; |
| rightPrecedenceRequirement = SHIFT; |
| break; |
| case ">>": |
| case "<<": |
| case ">>>": |
| leftPrecedenceRequirement = SHIFT; |
| rightPrecedenceRequirement = ADDITIVE; |
| break; |
| case "+": |
| case "-": |
| leftPrecedenceRequirement = ADDITIVE; |
| // We cannot remove parenthesis for "+" because |
| // x + (y + z) <!=> (x + y) + z: |
| // Example: |
| // "a" + (1 + 2) => "a3"; |
| // ("a" + 1) + 2 => "a12"; |
| rightPrecedenceRequirement = MULTIPLICATIVE; |
| break; |
| case "*": |
| case "/": |
| case "%": |
| leftPrecedenceRequirement = MULTIPLICATIVE; |
| // We cannot remove parenthesis for "*" because of precision issues. |
| rightPrecedenceRequirement = UNARY; |
| break; |
| default: |
| context.error("Forgot operator: $op"); |
| } |
| |
| visitNestedExpression(left, leftPrecedenceRequirement, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| |
| if (op == "in" || op == "instanceof") { |
| // There are cases where the space is not required but without further |
| // analysis we cannot know. |
| out(" "); |
| out(op); |
| out(" "); |
| } else { |
| if (leftSpace) spaceOut(); |
| out(op); |
| spaceOut(); |
| } |
| visitNestedExpression(right, rightPrecedenceRequirement, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitPrefix(Prefix unary) { |
| String op = unary.op; |
| switch (op) { |
| case "delete": |
| case "void": |
| case "typeof": |
| // There are cases where the space is not required but without further |
| // analysis we cannot know. |
| out(op); |
| out(" "); |
| break; |
| case "+": |
| case "++": |
| if (lastCharCode == charCodes.$PLUS) out(" "); |
| out(op); |
| break; |
| case "-": |
| case "--": |
| if (lastCharCode == charCodes.$MINUS) out(" "); |
| out(op); |
| break; |
| default: |
| out(op); |
| } |
| visitNestedExpression(unary.argument, unary.precedenceLevel, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitSpread(Spread unary) => visitPrefix(unary); |
| |
| @override |
| visitYield(Yield yield) { |
| out(yield.star ? "yield*" : "yield"); |
| if (yield.value == null) return; |
| out(" "); |
| visitNestedExpression(yield.value, yield.precedenceLevel, |
| newInForInit: inForInit, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitPostfix(Postfix postfix) { |
| visitNestedExpression(postfix.argument, LEFT_HAND_SIDE, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| out(postfix.op); |
| } |
| |
| @override |
| visitThis(This node) { |
| out("this"); |
| } |
| |
| @override |
| visitSuper(Super node) { |
| out("super"); |
| } |
| |
| @override |
| visitIdentifier(Identifier node) { |
| out(localNamer.getName(node)); |
| } |
| |
| @override |
| visitRestParameter(RestParameter node) { |
| out('...'); |
| visitIdentifier(node.parameter); |
| } |
| |
| bool isDigit(int charCode) { |
| return charCodes.$0 <= charCode && charCode <= charCodes.$9; |
| } |
| |
| bool isValidJavaScriptId(String field) { |
| if (field.length < 3) return false; |
| // Ignore the leading and trailing string-delimiter. |
| for (int i = 1; i < field.length - 1; i++) { |
| // TODO(floitsch): allow more characters. |
| int charCode = field.codeUnitAt(i); |
| if (!(charCodes.$a <= charCode && charCode <= charCodes.$z || |
| charCodes.$A <= charCode && charCode <= charCodes.$Z || |
| charCode == charCodes.$$ || |
| charCode == charCodes.$_ || |
| i != 1 && isDigit(charCode))) { |
| return false; |
| } |
| } |
| |
| // TODO(floitsch): normally we should also check that the field is not a |
| // reserved word. We don't generate fields with reserved word names except |
| // for 'super'. |
| return options.allowKeywordsInProperties || field != '"super"'; |
| } |
| |
| @override |
| visitAccess(PropertyAccess access) { |
| // Normally we can omit parens on the receiver if it is a Call, even though |
| // Call expressions have lower precedence. However this optimization doesn't |
| // work inside New expressions: |
| // |
| // new obj.foo().bar() |
| // |
| // This will be parsed as: |
| // |
| // (new obj.foo()).bar() |
| // |
| // Which is incorrect. So we must have parenthesis in this case: |
| // |
| // new (obj.foo()).bar() |
| // |
| int precedence = inNewTarget ? ACCESS : CALL; |
| |
| visitNestedExpression(access.receiver, precedence, |
| newInForInit: inForInit, newAtStatementBegin: atStatementBegin); |
| propertyNameOut(access.selector, inAccess: true); |
| } |
| |
| @override |
| visitNamedFunction(NamedFunction namedFunction) { |
| var f = namedFunction.function; |
| context.enterNode(f); |
| functionOut(f, namedFunction.name); |
| context.exitNode(f); |
| } |
| |
| @override |
| visitFun(Fun fun) { |
| functionOut(fun, null); |
| } |
| |
| @override |
| visitArrowFun(ArrowFun fun) { |
| localNamer.enterScope(fun); |
| if (fun.params.length == 1 && fun.params[0] is Identifier) { |
| visitNestedExpression(fun.params.single, SPREAD, |
| newInForInit: false, newAtStatementBegin: false); |
| } else { |
| out("("); |
| visitCommaSeparated(fun.params, SPREAD, |
| newInForInit: false, newAtStatementBegin: false); |
| out(")"); |
| } |
| spaceOut(); |
| out("=>"); |
| var body = fun.body; |
| if (body is Expression) { |
| spaceOut(); |
| // Object initializers require parenthesis to disambiguate |
| // AssignmentExpression from FunctionBody. See: |
| // https://tc39.github.io/ecma262/#sec-arrow-function-definitions |
| var needsParen = fun.body is ObjectInitializer; |
| if (needsParen) out("("); |
| visitNestedExpression(body, ASSIGNMENT, |
| newInForInit: false, newAtStatementBegin: false); |
| if (needsParen) out(")"); |
| } else { |
| blockBody(body as Block, needsSeparation: false, needsNewline: false); |
| } |
| localNamer.leaveScope(); |
| } |
| |
| @override |
| visitLiteralBool(LiteralBool node) { |
| out(node.value ? "true" : "false"); |
| } |
| |
| @override |
| visitLiteralString(LiteralString node) { |
| out(node.value); |
| } |
| |
| @override |
| visitLiteralNumber(LiteralNumber node) { |
| int charCode = node.value.codeUnitAt(0); |
| if (charCode == charCodes.$MINUS && lastCharCode == charCodes.$MINUS) { |
| out(" "); |
| } |
| out(node.value); |
| } |
| |
| @override |
| visitLiteralNull(LiteralNull node) { |
| out("null"); |
| } |
| |
| @override |
| visitArrayInitializer(ArrayInitializer node) { |
| out("["); |
| indentMore(); |
| var multiline = node.multiline; |
| List<Expression> elements = node.elements; |
| for (int i = 0; i < elements.length; i++) { |
| Expression element = elements[i]; |
| if (element is ArrayHole) { |
| // Note that array holes must have a trailing "," even if they are |
| // in last position. Otherwise `[,]` (having length 1) would become |
| // equal to `[]` (the empty array) |
| // and [1,,] (array with 1 and a hole) would become [1,] = [1]. |
| out(","); |
| continue; |
| } |
| if (i != 0 && !multiline) spaceOut(); |
| if (multiline) { |
| forceLine(); |
| indent(); |
| } |
| visitNestedExpression(element, ASSIGNMENT, |
| newInForInit: false, newAtStatementBegin: false); |
| // We can skip the trailing "," for the last element (since it's not |
| // an array hole). |
| if (i != elements.length - 1) out(","); |
| } |
| indentLess(); |
| if (multiline) { |
| lineOut(); |
| indent(); |
| } |
| out("]"); |
| } |
| |
| @override |
| visitArrayHole(ArrayHole node) { |
| throw "Unreachable"; |
| } |
| |
| @override |
| visitObjectInitializer(ObjectInitializer node) { |
| List<Property> properties = node.properties; |
| out("{"); |
| indentMore(); |
| |
| var multiline = node.multiline; |
| for (int i = 0; i < properties.length; i++) { |
| if (i != 0) { |
| out(","); |
| if (!multiline) spaceOut(); |
| } |
| if (multiline) { |
| forceLine(); |
| indent(); |
| } |
| visit(properties[i]); |
| } |
| indentLess(); |
| if (multiline) { |
| lineOut(); |
| indent(); |
| } |
| out("}"); |
| } |
| |
| @override |
| visitProperty(Property node) { |
| propertyNameOut(node.name); |
| out(":"); |
| spaceOut(); |
| visitNestedExpression(node.value, ASSIGNMENT, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| |
| @override |
| visitRegExpLiteral(RegExpLiteral node) { |
| out(node.pattern); |
| } |
| |
| @override |
| visitTemplateString(TemplateString node) { |
| out('`'); |
| int len = node.interpolations.length; |
| for (var i = 0; i < len; i++) { |
| out(node.strings[i]); |
| out(r'${'); |
| visit(node.interpolations[i]); |
| out('}'); |
| } |
| out(node.strings[len]); |
| out('`'); |
| } |
| |
| @override |
| visitTaggedTemplate(TaggedTemplate node) { |
| visit(node.tag); |
| visit(node.template); |
| } |
| |
| @override |
| visitClassDeclaration(ClassDeclaration node) { |
| indent(); |
| visit(node.classExpr); |
| lineOut(); |
| } |
| |
| @override |
| visitClassExpression(ClassExpression node) { |
| localNamer.enterScope(node); |
| out('class '); |
| visit(node.name); |
| if (node.heritage != null) { |
| out(' extends '); |
| visit(node.heritage); |
| } |
| spaceOut(); |
| if (node.methods.isNotEmpty) { |
| out('{'); |
| lineOut(); |
| indentMore(); |
| for (var method in node.methods) { |
| indent(); |
| visit(method); |
| lineOut(); |
| } |
| indentLess(); |
| indent(); |
| out('}'); |
| } else { |
| out('{}'); |
| } |
| localNamer.leaveScope(); |
| } |
| |
| @override |
| visitMethod(Method node) { |
| if (node.isStatic) { |
| out('static '); |
| } |
| if (node.isGetter) { |
| out('get '); |
| } else if (node.isSetter) { |
| out('set '); |
| } else if (node.function.isGenerator) { |
| out('*'); |
| } |
| propertyNameOut(node.name, inMethod: true); |
| |
| var fun = node.function; |
| localNamer.enterScope(fun); |
| out("("); |
| if (fun.params != null) { |
| visitCommaSeparated(fun.params, SPREAD, |
| newInForInit: false, newAtStatementBegin: false); |
| } |
| out(")"); |
| // TODO(jmesserly): async modifiers |
| if (fun.body.statements.isEmpty) { |
| spaceOut(); |
| out("{}"); |
| } else { |
| spaceOut(); |
| blockOut(fun.body, false, false); |
| } |
| localNamer.leaveScope(); |
| } |
| |
| void propertyNameOut(Expression node, |
| {bool inMethod = false, bool inAccess = false}) { |
| if (node is LiteralNumber) { |
| LiteralNumber nameNumber = node; |
| if (inAccess) out('['); |
| out(nameNumber.value); |
| if (inAccess) out(']'); |
| } else { |
| if (node is LiteralString) { |
| if (isValidJavaScriptId(node.value)) { |
| if (inAccess) out('.'); |
| out(node.valueWithoutQuotes); |
| } else { |
| if (inMethod || inAccess) out("["); |
| out(node.value); |
| if (inMethod || inAccess) out("]"); |
| } |
| } else { |
| // ComputedPropertyName |
| out("["); |
| visitNestedExpression(node, EXPRESSION, |
| newInForInit: false, newAtStatementBegin: false); |
| out("]"); |
| } |
| } |
| } |
| |
| @override |
| visitImportDeclaration(ImportDeclaration node) { |
| indent(); |
| out('import '); |
| if (node.defaultBinding != null) { |
| visit(node.defaultBinding); |
| if (node.namedImports != null) { |
| out(','); |
| spaceOut(); |
| } |
| } |
| nameSpecifierListOut(node.namedImports, false); |
| fromClauseOut(node.from); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitExportDeclaration(ExportDeclaration node) { |
| indent(); |
| out('export '); |
| if (node.isDefault) out('default '); |
| // TODO(jmesserly): we need to avoid indent/newline if this is a statement. |
| visit(node.exported); |
| outSemicolonLn(); |
| } |
| |
| @override |
| visitExportClause(ExportClause node) { |
| nameSpecifierListOut(node.exports, true); |
| fromClauseOut(node.from); |
| } |
| |
| nameSpecifierListOut(List<NameSpecifier> names, bool export) { |
| if (names == null) return; |
| |
| if (names.length == 1 && names[0].name.name == '*') { |
| nameSpecifierOut(names[0], export); |
| return; |
| } |
| |
| out('{'); |
| spaceOut(); |
| for (int i = 0; i < names.length; i++) { |
| if (i != 0) { |
| out(','); |
| spaceOut(); |
| } |
| nameSpecifierOut(names[i], export); |
| } |
| spaceOut(); |
| out('}'); |
| } |
| |
| fromClauseOut(LiteralString from) { |
| if (from != null) { |
| out(' from'); |
| spaceOut(); |
| out("'${from.valueWithoutQuotes}.js'"); |
| } |
| } |
| |
| /// This is unused, see [nameSpecifierOut]. |
| @override |
| visitNameSpecifier(NameSpecifier node) { |
| throw UnsupportedError('visitNameSpecifier'); |
| } |
| |
| nameSpecifierOut(NameSpecifier node, bool export) { |
| if (node.isStar) { |
| out('*'); |
| } else { |
| var localName = localNamer.getName(node.name); |
| if (node.asName == null) { |
| // If our local was renamed, generate an implicit "as". |
| // This is a convenience feature so imports and exports can be renamed. |
| var name = node.name.name; |
| if (localName != name) { |
| out(export ? localName : name); |
| out(' as '); |
| out(export ? name : localName); |
| return; |
| } |
| } |
| out(localName); |
| } |
| if (node.asName != null) { |
| out(' as '); |
| visitIdentifier(node.asName); |
| } |
| } |
| |
| @override |
| visitModule(Module node) { |
| visitAll(node.body); |
| } |
| |
| @override |
| visitLiteralExpression(LiteralExpression node) { |
| out(node.template); |
| } |
| |
| @override |
| visitLiteralStatement(LiteralStatement node) { |
| outLn(node.code); |
| } |
| |
| visitInterpolatedNode(InterpolatedNode node) { |
| out('#${node.nameOrPosition}'); |
| } |
| |
| @override |
| visitInterpolatedExpression(InterpolatedExpression node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedLiteral(InterpolatedLiteral node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedParameter(InterpolatedParameter node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedSelector(InterpolatedSelector node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedMethod(InterpolatedMethod node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedIdentifier(InterpolatedIdentifier node) => |
| visitInterpolatedNode(node); |
| |
| @override |
| visitInterpolatedStatement(InterpolatedStatement node) { |
| outLn('#${node.nameOrPosition}'); |
| } |
| |
| @override |
| void visitComment(Comment node) { |
| if (shouldCompressOutput) return; |
| String comment = node.comment.trim(); |
| if (comment.isEmpty) return; |
| for (var line in comment.split('\n')) { |
| if (comment.startsWith('//')) { |
| outIndentLn(line.trim()); |
| } else { |
| outIndentLn('// ${line.trim()}'); |
| } |
| } |
| } |
| |
| @override |
| void visitCommentExpression(CommentExpression node) { |
| if (shouldCompressOutput) return; |
| String comment = node.comment.trim(); |
| if (comment.isEmpty) return; |
| if (comment.startsWith('/*')) { |
| out(comment); |
| } else { |
| out('/* $comment */'); |
| } |
| visit(node.expression); |
| } |
| |
| @override |
| void visitAwait(Await node) { |
| out("await "); |
| visit(node.expression); |
| } |
| } |
| |
| // Collects all the var declarations in the function. We need to do this in a |
| // separate pass because JS vars are lifted to the top of the function. |
| class VarCollector extends BaseVisitor { |
| bool nested; |
| final Set<String> vars; |
| final Set<String> params; |
| |
| VarCollector() |
| : nested = false, |
| vars = Set<String>(), |
| params = Set<String>(); |
| |
| void forEachVar(void fn(String v)) => vars.forEach(fn); |
| void forEachParam(void fn(String p)) => params.forEach(fn); |
| |
| void collectVarsInFunction(FunctionExpression fun) { |
| if (!nested) { |
| nested = true; |
| if (fun.params != null) { |
| for (var param in fun.params) { |
| // TODO(jmesserly): add ES6 support. Currently not needed because |
| // dart2js does not emit ES6 rest param or destructuring. |
| params.add((param as Identifier).name); |
| } |
| } |
| fun.body.accept(this); |
| nested = false; |
| } |
| } |
| |
| @override |
| void visitFunctionDeclaration(FunctionDeclaration declaration) { |
| // Note that we don't bother collecting the name of the function. |
| collectVarsInFunction(declaration.function); |
| } |
| |
| @override |
| void visitNamedFunction(NamedFunction namedFunction) { |
| // Note that we don't bother collecting the name of the function. |
| collectVarsInFunction(namedFunction.function); |
| } |
| |
| @override |
| void visitMethod(Method declaration) { |
| collectVarsInFunction(declaration.function); |
| } |
| |
| @override |
| void visitFun(Fun fun) { |
| collectVarsInFunction(fun); |
| } |
| |
| @override |
| void visitArrowFun(ArrowFun fun) { |
| collectVarsInFunction(fun); |
| } |
| |
| @override |
| void visitClassExpression(ClassExpression node) { |
| // Note that we don't bother collecting the name of the class. |
| if (node.heritage != null) node.heritage.accept(this); |
| for (Method method in node.methods) { |
| method.accept(this); |
| } |
| } |
| |
| @override |
| void visitCatch(Catch node) { |
| declareVariable(node.declaration); |
| node.body.accept(this); |
| } |
| |
| @override |
| void visitVariableInitialization(VariableInitialization node) { |
| // TODO(jmesserly): add ES6 support. Currently not needed because |
| // dart2js does not emit ES6 rest param or destructuring. |
| declareVariable(node.declaration as Identifier); |
| node.value?.accept(this); |
| } |
| |
| void declareVariable(Identifier decl) { |
| if (decl.allowRename) vars.add(decl.name); |
| } |
| } |
| |
| /** |
| * Returns true, if the given node must be wrapped into braces when used |
| * as then-statement in an [If] that has an else branch. |
| */ |
| class DanglingElseVisitor extends BaseVisitor<bool> { |
| JavaScriptPrintingContext context; |
| |
| DanglingElseVisitor(this.context); |
| |
| @override |
| bool visitProgram(Program node) => false; |
| |
| @override |
| bool visitNode(Node node) { |
| context.error("Forgot node: $node"); |
| return null; |
| } |
| |
| @override |
| bool visitBlock(Block node) => false; |
| @override |
| bool visitExpressionStatement(ExpressionStatement node) => false; |
| @override |
| bool visitEmptyStatement(EmptyStatement node) => false; |
| @override |
| bool visitIf(If node) { |
| if (!node.hasElse) return true; |
| return node.otherwise.accept(this); |
| } |
| |
| @override |
| bool visitFor(For node) => node.body.accept(this); |
| @override |
| bool visitForIn(ForIn node) => node.body.accept(this); |
| @override |
| bool visitForOf(ForOf node) => node.body.accept(this); |
| @override |
| bool visitWhile(While node) => node.body.accept(this); |
| @override |
| bool visitDo(Do node) => false; |
| @override |
| bool visitContinue(Continue node) => false; |
| @override |
| bool visitBreak(Break node) => false; |
| @override |
| bool visitReturn(Return node) => false; |
| @override |
| bool visitThrow(Throw node) => false; |
| @override |
| bool visitTry(Try node) { |
| if (node.finallyPart != null) { |
| return node.finallyPart.accept(this); |
| } else { |
| return node.catchPart.accept(this); |
| } |
| } |
| |
| @override |
| bool visitCatch(Catch node) => node.body.accept(this); |
| @override |
| bool visitSwitch(Switch node) => false; |
| @override |
| bool visitSwitchCase(SwitchCase node) => false; |
| @override |
| bool visitFunctionDeclaration(FunctionDeclaration node) => false; |
| @override |
| bool visitLabeledStatement(LabeledStatement node) => node.body.accept(this); |
| @override |
| bool visitLiteralStatement(LiteralStatement node) => true; |
| @override |
| bool visitClassDeclaration(ClassDeclaration node) => false; |
| |
| @override |
| bool visitExpression(Expression node) => false; |
| } |
| |
| abstract class LocalNamer { |
| String getName(Identifier node); |
| void enterScope(Node node); |
| void leaveScope(); |
| } |
| |
| class IdentityNamer implements LocalNamer { |
| @override |
| String getName(Identifier node) => node.name; |
| @override |
| void enterScope(Node node) {} |
| @override |
| void leaveScope() {} |
| } |
| |
| class MinifyRenamer implements LocalNamer { |
| final List<Map<String, String>> maps = []; |
| final List<int> parameterNumberStack = []; |
| final List<int> variableNumberStack = []; |
| int parameterNumber = 0; |
| int variableNumber = 0; |
| |
| @override |
| void enterScope(Node node) { |
| var vars = VarCollector(); |
| node.accept(vars); |
| maps.add(Map<String, String>()); |
| variableNumberStack.add(variableNumber); |
| parameterNumberStack.add(parameterNumber); |
| vars.forEachVar(declareVariable); |
| vars.forEachParam(declareParameter); |
| } |
| |
| @override |
| void leaveScope() { |
| maps.removeLast(); |
| variableNumber = variableNumberStack.removeLast(); |
| parameterNumber = parameterNumberStack.removeLast(); |
| } |
| |
| @override |
| String getName(Identifier node) { |
| String oldName = node.name; |
| // Go from inner scope to outer looking for mapping of name. |
| for (int i = maps.length - 1; i >= 0; i--) { |
| var map = maps[i]; |
| var replacement = map[oldName]; |
| if (replacement != null) return replacement; |
| } |
| return oldName; |
| } |
| |
| static const LOWER_CASE_LETTERS = 26; |
| static const LETTERS = LOWER_CASE_LETTERS; |
| static const DIGITS = 10; |
| |
| static int nthLetter(int n) { |
| return (n < LOWER_CASE_LETTERS) |
| ? charCodes.$a + n |
| : charCodes.$A + n - LOWER_CASE_LETTERS; |
| } |
| |
| // Parameters go from a to z and variables go from z to a. This makes each |
| // argument list and each top-of-function var declaration look similar and |
| // helps gzip compress the file. If we have more than 26 arguments and |
| // variables then we meet somewhere in the middle of the alphabet. After |
| // that we give up trying to be nice to the compression algorithm and just |
| // use the same namespace for arguments and variables, starting with A, and |
| // moving on to a0, a1, etc. |
| String declareVariable(String oldName) { |
| if (avoidRenaming(oldName)) return oldName; |
| String newName; |
| if (variableNumber + parameterNumber < LOWER_CASE_LETTERS) { |
| // Variables start from z and go backwards, for better gzipability. |
| newName = getNameNumber(oldName, LOWER_CASE_LETTERS - 1 - variableNumber); |
| } else { |
| // After 26 variables and parameters we allocate them in the same order. |
| newName = getNameNumber(oldName, variableNumber + parameterNumber); |
| } |
| variableNumber++; |
| return newName; |
| } |
| |
| String declareParameter(String oldName) { |
| if (avoidRenaming(oldName)) return oldName; |
| String newName; |
| if (variableNumber + parameterNumber < LOWER_CASE_LETTERS) { |
| newName = getNameNumber(oldName, parameterNumber); |
| } else { |
| newName = getNameNumber(oldName, variableNumber + parameterNumber); |
| } |
| parameterNumber++; |
| return newName; |
| } |
| |
| bool avoidRenaming(String oldName) { |
| // Variables of this $form$ are used in pattern matching the message of JS |
| // exceptions, so should not be renamed. |
| // TODO(sra): Introduce a way for indicating in the JS text which variables |
| // should not be renamed. |
| return oldName.startsWith(r'$') && oldName.endsWith(r'$'); |
| } |
| |
| String getNameNumber(String oldName, int n) { |
| if (maps.isEmpty) return oldName; |
| |
| String newName; |
| if (n < LETTERS) { |
| // Start naming variables a, b, c, ..., z, A, B, C, ..., Z. |
| newName = String.fromCharCodes([nthLetter(n)]); |
| } else { |
| // Then name variables a0, a1, a2, ..., a9, b0, b1, ..., Z9, aa0, aa1, ... |
| // For all functions with fewer than 500 locals this is just as compact |
| // as using aa, ab, etc. but avoids clashes with keywords. |
| n -= LETTERS; |
| int digit = n % DIGITS; |
| n ~/= DIGITS; |
| int alphaChars = 1; |
| int nameSpaceSize = LETTERS; |
| // Find out whether we should use the 1-character namespace (size 52), the |
| // 2-character namespace (size 52*52), etc. |
| while (n >= nameSpaceSize) { |
| n -= nameSpaceSize; |
| alphaChars++; |
| nameSpaceSize *= LETTERS; |
| } |
| var codes = <int>[]; |
| for (var i = 0; i < alphaChars; i++) { |
| nameSpaceSize ~/= LETTERS; |
| codes.add(nthLetter((n ~/ nameSpaceSize) % LETTERS)); |
| } |
| codes.add(charCodes.$0 + digit); |
| newName = String.fromCharCodes(codes); |
| } |
| assert(RegExp(r'[a-zA-Z][a-zA-Z0-9]*').hasMatch(newName)); |
| maps.last[oldName] = newName; |
| return newName; |
| } |
| } |
| |
| /// Like [BaseVisitor], but calls [declare] for [Identifier] declarations, and |
| /// [visitIdentifier] otherwise. |
| abstract class VariableDeclarationVisitor extends BaseVisitor<void> { |
| declare(Identifier node); |
| |
| @override |
| visitFunctionExpression(FunctionExpression node) { |
| node.params.forEach(_scanVariableBinding); |
| node.body.accept(this); |
| } |
| |
| _scanVariableBinding(VariableBinding d) { |
| if (d is Identifier) { |
| declare(d); |
| } else { |
| d.accept(this); |
| } |
| } |
| |
| @override |
| visitRestParameter(RestParameter node) { |
| _scanVariableBinding(node.parameter); |
| super.visitRestParameter(node); |
| } |
| |
| @override |
| visitDestructuredVariable(DestructuredVariable node) { |
| var name = node.name; |
| if (name is Identifier) _scanVariableBinding(name); |
| super.visitDestructuredVariable(node); |
| } |
| |
| @override |
| visitSimpleBindingPattern(SimpleBindingPattern node) { |
| _scanVariableBinding(node.name); |
| super.visitSimpleBindingPattern(node); |
| } |
| |
| @override |
| visitVariableInitialization(VariableInitialization node) { |
| _scanVariableBinding(node.declaration); |
| if (node.value != null) node.value.accept(this); |
| } |
| |
| @override |
| visitCatch(Catch node) { |
| declare(node.declaration); |
| node.body.accept(this); |
| } |
| |
| @override |
| visitFunctionDeclaration(FunctionDeclaration node) { |
| declare(node.name); |
| node.function.accept(this); |
| } |
| |
| @override |
| visitNamedFunction(NamedFunction node) { |
| declare(node.name); |
| node.function.accept(this); |
| } |
| |
| @override |
| visitClassExpression(ClassExpression node) { |
| declare(node.name); |
| if (node.heritage != null) node.heritage.accept(this); |
| for (Method element in node.methods) { |
| element.accept(this); |
| } |
| } |
| } |
