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initial revision of downlevel compilation for let/const bindings

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This commit is contained in:
Vladimir Matveev
2015-02-14 00:48:46 -08:00
parent b1dc910b4a
commit a0bcd7eabf
3 changed files with 237 additions and 39 deletions
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src/compiler/checker.ts
+26 -11
View File
@@ -264,7 +264,7 @@ module ts {
Debug.assert((symbol.flags & SymbolFlags.Instantiated) === 0, "Should never get an instantiated symbol here.");
if (symbol.flags & meaning) {
return symbol;
}
}
if (symbol.flags & SymbolFlags.Import) {
var target = resolveImport(symbol);
@@ -10207,7 +10207,30 @@ module ts {
}
function isUnknownIdentifier(location: Node, name: string): boolean {
return !resolveName(location, name, SymbolFlags.Value, /*nodeNotFoundMessage*/ undefined, /*nameArg*/ undefined);
return !resolveName(location, name, SymbolFlags.Value | SymbolFlags.Import, /*nodeNotFoundMessage*/ undefined, /*nameArg*/ undefined);
}
function getBlockScopedVariableId(n: Identifier): number {
Debug.assert(n.parent !== undefined);
// ignore name parts of property access expressions
if (n.parent.kind === SyntaxKind.PropertyAccessExpression &&
(<PropertyAccessExpression>n.parent).name === n) {
return undefined;
}
// for names in variable declarations and binding elements try to short circuit and fetch symbol from the node
var declarationSymbol: Symbol =
(n.parent.kind === SyntaxKind.VariableDeclaration && (<VariableDeclaration>n.parent).name === n) ||
n.parent.kind === SyntaxKind.BindingElement
? getSymbolOfNode(n.parent)
: undefined;
var symbol = declarationSymbol ||
getNodeLinks(n).resolvedSymbol ||
resolveName(n, n.text, SymbolFlags.BlockScopedVariable | SymbolFlags.Import, /*nodeNotFoundMessage*/ undefined, /*nameArg*/ undefined);
return symbol && symbol.flags & SymbolFlags.BlockScopedVariable ? symbol.id : undefined;
}
function createResolver(): EmitResolver {
@@ -10226,6 +10249,7 @@ module ts {
isEntityNameVisible,
getConstantValue,
isUnknownIdentifier,
getBlockScopedVariableId,
};
}
@@ -10953,15 +10977,6 @@ module ts {
if (!declarationList.declarations.length) {
return grammarErrorAtPos(getSourceFileOfNode(declarationList), declarations.pos, declarations.end - declarations.pos, Diagnostics.Variable_declaration_list_cannot_be_empty);
}
if (languageVersion < ScriptTarget.ES6) {
if (isLet(declarationList)) {
return grammarErrorOnFirstToken(declarationList, Diagnostics.let_declarations_are_only_available_when_targeting_ECMAScript_6_and_higher);
}
else if (isConst(declarationList)) {
return grammarErrorOnFirstToken(declarationList, Diagnostics.const_declarations_are_only_available_when_targeting_ECMAScript_6_and_higher);
}
}
}
function allowLetAndConstDeclarations(parent: Node): boolean {
src/compiler/emitter.ts
+210 -28
View File
@@ -21,6 +21,12 @@ module ts {
diagnosticMessage: DiagnosticMessage;
typeName?: DeclarationName;
}
interface ScopeFrame {
names: Map<string>;
previous: ScopeFrame;
}
type GetSymbolAccessibilityDiagnostic = (symbolAccesibilityResult: SymbolAccessiblityResult) => SymbolAccessibilityDiagnostic;
interface EmitTextWriterWithSymbolWriter extends EmitTextWriter, SymbolWriter {
@@ -353,7 +359,6 @@ module ts {
var enclosingDeclaration: Node;
var currentSourceFile: SourceFile;
var reportedDeclarationError = false;
var emitJsDocComments = compilerOptions.removeComments ? function (declaration: Node) { } : writeJsDocComments;
var emit = compilerOptions.stripInternal ? stripInternal : emitNode;
@@ -1557,6 +1562,11 @@ module ts {
var currentSourceFile: SourceFile;
var lastFrame: ScopeFrame;
var currentScopeNames: Map<string>;
var generatedBlockScopeNames: string[];
var extendsEmitted = false;
var tempCount = 0;
var tempVariables: Identifier[];
@@ -1629,6 +1639,82 @@ module ts {
writeEmittedFiles(writer.getText(), /*writeByteOrderMark*/ compilerOptions.emitBOM);
return;
function enterScope(): boolean {
var names = currentScopeNames;
currentScopeNames = undefined;
if (names) {
lastFrame = { names, previous: lastFrame };
return true;
}
return false;
}
function exitScope(popFrame: boolean): void {
if (popFrame) {
currentScopeNames = lastFrame.names;
lastFrame = lastFrame.previous;
}
else {
currentScopeNames = undefined;
}
}
function makeUniqueName(location: Node, baseName: string): string {
if (!isExistingName(location, baseName)) {
// use current name as is
return setGeneratedName(baseName);
}
// First try '_name'
if (baseName.charCodeAt(0) !== CharacterCodes._) {
var baseName = "_" + baseName;
if (!isExistingName(location, baseName)) {
return setGeneratedName(baseName);
}
}
// Find the first unique '_name_n', where n is a positive number
if (baseName.charCodeAt(baseName.length - 1) !== CharacterCodes._) {
baseName += "_";
}
var i = 1;
while (true) {
name = baseName + i;
if (!isExistingName(location, name)) {
return setGeneratedName(name);
}
i++;
}
}
function setGeneratedName(name: string): string {
if (!currentScopeNames) {
currentScopeNames = {};
}
return currentScopeNames[name] = name;
}
function isExistingName(location: Node, name: string) {
if (!resolver.isUnknownIdentifier(location, name)) {
return true;
}
if (currentScopeNames && hasProperty(currentScopeNames, name)) {
return true;
}
var frame = lastFrame;
while (frame) {
if (hasProperty(frame.names, name)) {
return true;
}
frame = frame.previous;
}
return false;
}
function initializeEmitterWithSourceMaps() {
var sourceMapDir: string; // The directory in which sourcemap will be
@@ -1990,7 +2076,7 @@ module ts {
function createTempVariable(location: Node, forLoopVariable?: boolean): Identifier {
var name = forLoopVariable ? "_i" : undefined;
while (true) {
if (name && resolver.isUnknownIdentifier(location, name)) {
if (name && !isExistingName(location, name)) {
break;
}
// _a .. _h, _j ... _z, _0, _1, ...
@@ -2338,7 +2424,20 @@ module ts {
writeTextOfNode(currentSourceFile, node);
}
function getBlockScopedVariableId(node: Identifier): number {
// return undefined for synthesized nodes
return node.parent && resolver.getBlockScopedVariableId(node);
}
function emitIdentifier(node: Identifier) {
var symbolId = getBlockScopedVariableId(node);
if (symbolId !== undefined && generatedBlockScopeNames) {
var text = generatedBlockScopeNames[symbolId];
if (text) {
write(text);
return;
}
}
if (!node.parent) {
write(node.text);
}
@@ -2881,6 +2980,32 @@ module ts {
emitEmbeddedStatement(node.statement);
}
function emitStartOfVariableDeclarationList(decl: Node, startPos?: number): void {
var tokenKind = SyntaxKind.VarKeyword;
if (decl && languageVersion >= ScriptTarget.ES6) {
if (isLet(decl)) {
tokenKind = SyntaxKind.LetKeyword;
}
else if (isConst(decl)) {
tokenKind = SyntaxKind.ConstKeyword;
}
}
if (startPos !== undefined) {
emitToken(tokenKind, startPos);
}
else {
switch (tokenKind) {
case SyntaxKind.VarKeyword:
return write("var ");
case SyntaxKind.LetKeyword:
return write("let ");
case SyntaxKind.ConstKeyword:
return write("const ");
}
}
}
function emitForStatement(node: ForStatement) {
var endPos = emitToken(SyntaxKind.ForKeyword, node.pos);
write(" ");
@@ -2888,17 +3013,9 @@ module ts {
if (node.initializer && node.initializer.kind === SyntaxKind.VariableDeclarationList) {
var variableDeclarationList = <VariableDeclarationList>node.initializer;
var declarations = variableDeclarationList.declarations;
if (declarations[0] && isLet(declarations[0])) {
emitToken(SyntaxKind.LetKeyword, endPos);
}
else if (declarations[0] && isConst(declarations[0])) {
emitToken(SyntaxKind.ConstKeyword, endPos);
}
else {
emitToken(SyntaxKind.VarKeyword, endPos);
}
emitStartOfVariableDeclarationList(declarations[0], endPos);
write(" ");
emitCommaList(variableDeclarationList.declarations);
emitCommaList(declarations);
}
else if (node.initializer) {
emit(node.initializer);
@@ -2919,12 +3036,7 @@ module ts {
var variableDeclarationList = <VariableDeclarationList>node.initializer;
if (variableDeclarationList.declarations.length >= 1) {
var decl = variableDeclarationList.declarations[0];
if (isLet(decl)) {
emitToken(SyntaxKind.LetKeyword, endPos);
}
else {
emitToken(SyntaxKind.VarKeyword, endPos);
}
emitStartOfVariableDeclarationList(decl, endPos);
write(" ");
emit(decl);
}
@@ -3075,6 +3187,8 @@ module ts {
if (emitCount++) {
write(", ");
}
renameNonTopLevelLetAndConst(name);
if (name.parent && (name.parent.kind === SyntaxKind.VariableDeclaration || name.parent.kind === SyntaxKind.BindingElement)) {
emitModuleMemberName(<Declaration>name.parent);
}
@@ -3184,7 +3298,7 @@ module ts {
emitDestructuringAssignment(e, createElementAccess(value, createNumericLiteral(i)));
}
else {
if (i === elements.length - 1) {
if (i === elements.length - 1 && (<SpreadElementExpression>e).expression.kind === SyntaxKind.Identifier) {
value = ensureIdentifier(value);
emitAssignment(<Identifier>(<SpreadElementExpression>e).expression, value);
write(".slice(" + i + ")");
@@ -3286,22 +3400,75 @@ module ts {
}
}
else {
renameNonTopLevelLetAndConst(<Identifier>node.name);
emitModuleMemberName(node);
emitOptional(" = ", node.initializer);
}
}
function getEnclosingBlockScopeContainer(node: Node): Node {
var current = node;
while (current) {
if (isAnyFunction(current)) {
return current.parent;
}
switch (current.kind) {
case SyntaxKind.CatchClause:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.SwitchKeyword:
return current.parent;
case SyntaxKind.Block:
if (isAnyFunction(current.parent)) {
return current.parent.parent;
}
else {
return current.parent;
}
case SyntaxKind.SourceFile:
return current;
}
current = current.parent;
}
}
function renameNonTopLevelLetAndConst(node: Node): void {
// do not rename if
// - language version is ES6+
// - node is synthesized (does not have a parent)
// - node is definitely not name of variable declaration.
// it still can be part of parameter declaration, this check will be done next
if (languageVersion >= ScriptTarget.ES6 ||
!node.parent ||
(node.parent.kind !== SyntaxKind.VariableDeclaration && node.parent.kind !== SyntaxKind.BindingElement)) {
return;
}
var combinedFlags = getCombinedNodeFlags(node.parent);
if (((combinedFlags & NodeFlags.BlockScoped) === 0) || combinedFlags & NodeFlags.Export) {
// do not rename exported or non-block scoped variables
return;
}
// here it is known that node is a block scoped variable
var list = getAncestor(node, SyntaxKind.VariableDeclarationList);
if (list.parent.kind === SyntaxKind.VariableStatement && list.parent.parent.kind === SyntaxKind.SourceFile) {
// do not rename variables that are defined on source file level
return;
}
var generatedName = makeUniqueName(getEnclosingBlockScopeContainer(node), (<Identifier>node).text);
var symbolId = resolver.getBlockScopedVariableId(<Identifier>node);
if (!generatedBlockScopeNames) {
generatedBlockScopeNames = [];
}
generatedBlockScopeNames[symbolId] = generatedName;
}
function emitVariableStatement(node: VariableStatement) {
if (!(node.flags & NodeFlags.Export)) {
if (isLet(node.declarationList)) {
write("let ");
}
else if (isConst(node.declarationList)) {
write("const ");
}
else {
write("var ");
}
emitStartOfVariableDeclarationList(node.declarationList);
}
emitCommaList(node.declarationList.declarations);
write(";");
@@ -3472,6 +3639,8 @@ module ts {
tempVariables = undefined;
tempParameters = undefined;
var popFrame = enterScope()
// When targeting ES6, emit arrow function natively in ES6
if (shouldEmitAsArrowFunction(node)) {
emitSignatureParametersForArrow(node);
@@ -3563,6 +3732,9 @@ module ts {
emitEnd(node);
write(";");
}
exitScope(popFrame);
tempCount = saveTempCount;
tempVariables = saveTempVariables;
tempParameters = saveTempParameters;
@@ -3773,6 +3945,9 @@ module ts {
tempCount = 0;
tempVariables = undefined;
tempParameters = undefined;
var popFrame = enterScope();
// Emit the constructor overload pinned comments
forEach(node.members, member => {
if (member.kind === SyntaxKind.Constructor && !(<ConstructorDeclaration>member).body) {
@@ -3833,6 +4008,9 @@ module ts {
if (ctor) {
emitTrailingComments(ctor);
}
exitScope(popFrame);
tempCount = saveTempCount;
tempVariables = saveTempVariables;
tempParameters = saveTempParameters;
@@ -3962,7 +4140,11 @@ module ts {
var saveTempVariables = tempVariables;
tempCount = 0;
tempVariables = undefined;
var popFrame = enterScope();
emit(node.body);
exitScope(popFrame);
tempCount = saveTempCount;
tempVariables = saveTempVariables;
}
src/compiler/types.ts
+1
View File
@@ -1138,6 +1138,7 @@ module ts {
// Returns the constant value this property access resolves to, or 'undefined' for a non-constant
getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): number;
isUnknownIdentifier(location: Node, name: string): boolean;
getBlockScopedVariableId(node: Identifier): number;
}
export const enum SymbolFlags {