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Copy pathparser.ts
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5420 lines (4743 loc) · 263 KB
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/// <reference path="scanner.ts"/>
/// <reference path="utilities.ts"/>
module ts {
let nodeConstructors = new Array<new () => Node>(SyntaxKind.Count);
/* @internal */ export let parseTime = 0;
export function getNodeConstructor(kind: SyntaxKind): new () => Node {
return nodeConstructors[kind] || (nodeConstructors[kind] = objectAllocator.getNodeConstructor(kind));
}
export function createNode(kind: SyntaxKind): Node {
return new (getNodeConstructor(kind))();
}
function visitNode<T>(cbNode: (node: Node) => T, node: Node): T {
if (node) {
return cbNode(node);
}
}
function visitNodeArray<T>(cbNodes: (nodes: Node[]) => T, nodes: Node[]) {
if (nodes) {
return cbNodes(nodes);
}
}
function visitEachNode<T>(cbNode: (node: Node) => T, nodes: Node[]) {
if (nodes) {
for (let node of nodes) {
let result = cbNode(node);
if (result) {
return result;
}
}
}
}
// Invokes a callback for each child of the given node. The 'cbNode' callback is invoked for all child nodes
// stored in properties. If a 'cbNodes' callback is specified, it is invoked for embedded arrays; otherwise,
// embedded arrays are flattened and the 'cbNode' callback is invoked for each element. If a callback returns
// a truthy value, iteration stops and that value is returned. Otherwise, undefined is returned.
export function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T {
if (!node) {
return;
}
// The visitXXX functions could be written as local functions that close over the cbNode and cbNodeArray
// callback parameters, but that causes a closure allocation for each invocation with noticeable effects
// on performance.
let visitNodes: (cb: (node: Node | Node[]) => T, nodes: Node[]) => T = cbNodeArray ? visitNodeArray : visitEachNode;
let cbNodes = cbNodeArray || cbNode;
switch (node.kind) {
case SyntaxKind.QualifiedName:
return visitNode(cbNode, (<QualifiedName>node).left) ||
visitNode(cbNode, (<QualifiedName>node).right);
case SyntaxKind.TypeParameter:
return visitNode(cbNode, (<TypeParameterDeclaration>node).name) ||
visitNode(cbNode, (<TypeParameterDeclaration>node).constraint) ||
visitNode(cbNode, (<TypeParameterDeclaration>node).expression);
case SyntaxKind.Parameter:
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.PropertyAssignment:
case SyntaxKind.ShorthandPropertyAssignment:
case SyntaxKind.VariableDeclaration:
case SyntaxKind.BindingElement:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).propertyName) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).dotDotDotToken) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).name) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).questionToken) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).type) ||
visitNode(cbNode, (<VariableLikeDeclaration>node).initializer);
case SyntaxKind.FunctionType:
case SyntaxKind.ConstructorType:
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.IndexSignature:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNodes(cbNodes, (<SignatureDeclaration>node).typeParameters) ||
visitNodes(cbNodes, (<SignatureDeclaration>node).parameters) ||
visitNode(cbNode, (<SignatureDeclaration>node).type);
case SyntaxKind.MethodDeclaration:
case SyntaxKind.MethodSignature:
case SyntaxKind.Constructor:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.FunctionExpression:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ArrowFunction:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<FunctionLikeDeclaration>node).asteriskToken) ||
visitNode(cbNode, (<FunctionLikeDeclaration>node).name) ||
visitNode(cbNode, (<FunctionLikeDeclaration>node).questionToken) ||
visitNodes(cbNodes, (<FunctionLikeDeclaration>node).typeParameters) ||
visitNodes(cbNodes, (<FunctionLikeDeclaration>node).parameters) ||
visitNode(cbNode, (<FunctionLikeDeclaration>node).type) ||
visitNode(cbNode, (<ArrowFunction>node).equalsGreaterThanToken) ||
visitNode(cbNode, (<FunctionLikeDeclaration>node).body);
case SyntaxKind.TypeReference:
return visitNode(cbNode, (<TypeReferenceNode>node).typeName) ||
visitNodes(cbNodes, (<TypeReferenceNode>node).typeArguments);
case SyntaxKind.TypeQuery:
return visitNode(cbNode, (<TypeQueryNode>node).exprName);
case SyntaxKind.TypeLiteral:
return visitNodes(cbNodes, (<TypeLiteralNode>node).members);
case SyntaxKind.ArrayType:
return visitNode(cbNode, (<ArrayTypeNode>node).elementType);
case SyntaxKind.TupleType:
return visitNodes(cbNodes, (<TupleTypeNode>node).elementTypes);
case SyntaxKind.UnionType:
return visitNodes(cbNodes, (<UnionTypeNode>node).types);
case SyntaxKind.ParenthesizedType:
return visitNode(cbNode, (<ParenthesizedTypeNode>node).type);
case SyntaxKind.ObjectBindingPattern:
case SyntaxKind.ArrayBindingPattern:
return visitNodes(cbNodes, (<BindingPattern>node).elements);
case SyntaxKind.ArrayLiteralExpression:
return visitNodes(cbNodes, (<ArrayLiteralExpression>node).elements);
case SyntaxKind.ObjectLiteralExpression:
return visitNodes(cbNodes, (<ObjectLiteralExpression>node).properties);
case SyntaxKind.PropertyAccessExpression:
return visitNode(cbNode, (<PropertyAccessExpression>node).expression) ||
visitNode(cbNode, (<PropertyAccessExpression>node).dotToken) ||
visitNode(cbNode, (<PropertyAccessExpression>node).name);
case SyntaxKind.ElementAccessExpression:
return visitNode(cbNode, (<ElementAccessExpression>node).expression) ||
visitNode(cbNode, (<ElementAccessExpression>node).argumentExpression);
case SyntaxKind.CallExpression:
case SyntaxKind.NewExpression:
return visitNode(cbNode, (<CallExpression>node).expression) ||
visitNodes(cbNodes, (<CallExpression>node).typeArguments) ||
visitNodes(cbNodes, (<CallExpression>node).arguments);
case SyntaxKind.TaggedTemplateExpression:
return visitNode(cbNode, (<TaggedTemplateExpression>node).tag) ||
visitNode(cbNode, (<TaggedTemplateExpression>node).template);
case SyntaxKind.TypeAssertionExpression:
return visitNode(cbNode, (<TypeAssertion>node).type) ||
visitNode(cbNode, (<TypeAssertion>node).expression);
case SyntaxKind.ParenthesizedExpression:
return visitNode(cbNode, (<ParenthesizedExpression>node).expression);
case SyntaxKind.DeleteExpression:
return visitNode(cbNode, (<DeleteExpression>node).expression);
case SyntaxKind.TypeOfExpression:
return visitNode(cbNode, (<TypeOfExpression>node).expression);
case SyntaxKind.VoidExpression:
return visitNode(cbNode, (<VoidExpression>node).expression);
case SyntaxKind.PrefixUnaryExpression:
return visitNode(cbNode, (<PrefixUnaryExpression>node).operand);
case SyntaxKind.YieldExpression:
return visitNode(cbNode, (<YieldExpression>node).asteriskToken) ||
visitNode(cbNode, (<YieldExpression>node).expression);
case SyntaxKind.PostfixUnaryExpression:
return visitNode(cbNode, (<PostfixUnaryExpression>node).operand);
case SyntaxKind.BinaryExpression:
return visitNode(cbNode, (<BinaryExpression>node).left) ||
visitNode(cbNode, (<BinaryExpression>node).operatorToken) ||
visitNode(cbNode, (<BinaryExpression>node).right);
case SyntaxKind.ConditionalExpression:
return visitNode(cbNode, (<ConditionalExpression>node).condition) ||
visitNode(cbNode, (<ConditionalExpression>node).questionToken) ||
visitNode(cbNode, (<ConditionalExpression>node).whenTrue) ||
visitNode(cbNode, (<ConditionalExpression>node).colonToken) ||
visitNode(cbNode, (<ConditionalExpression>node).whenFalse);
case SyntaxKind.SpreadElementExpression:
return visitNode(cbNode, (<SpreadElementExpression>node).expression);
case SyntaxKind.Block:
case SyntaxKind.ModuleBlock:
return visitNodes(cbNodes, (<Block>node).statements);
case SyntaxKind.SourceFile:
return visitNodes(cbNodes, (<SourceFile>node).statements) ||
visitNode(cbNode, (<SourceFile>node).endOfFileToken);
case SyntaxKind.VariableStatement:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<VariableStatement>node).declarationList);
case SyntaxKind.VariableDeclarationList:
return visitNodes(cbNodes, (<VariableDeclarationList>node).declarations);
case SyntaxKind.ExpressionStatement:
return visitNode(cbNode, (<ExpressionStatement>node).expression);
case SyntaxKind.IfStatement:
return visitNode(cbNode, (<IfStatement>node).expression) ||
visitNode(cbNode, (<IfStatement>node).thenStatement) ||
visitNode(cbNode, (<IfStatement>node).elseStatement);
case SyntaxKind.DoStatement:
return visitNode(cbNode, (<DoStatement>node).statement) ||
visitNode(cbNode, (<DoStatement>node).expression);
case SyntaxKind.WhileStatement:
return visitNode(cbNode, (<WhileStatement>node).expression) ||
visitNode(cbNode, (<WhileStatement>node).statement);
case SyntaxKind.ForStatement:
return visitNode(cbNode, (<ForStatement>node).initializer) ||
visitNode(cbNode, (<ForStatement>node).condition) ||
visitNode(cbNode, (<ForStatement>node).iterator) ||
visitNode(cbNode, (<ForStatement>node).statement);
case SyntaxKind.ForInStatement:
return visitNode(cbNode, (<ForInStatement>node).initializer) ||
visitNode(cbNode, (<ForInStatement>node).expression) ||
visitNode(cbNode, (<ForInStatement>node).statement);
case SyntaxKind.ForOfStatement:
return visitNode(cbNode, (<ForOfStatement>node).initializer) ||
visitNode(cbNode, (<ForOfStatement>node).expression) ||
visitNode(cbNode, (<ForOfStatement>node).statement);
case SyntaxKind.ContinueStatement:
case SyntaxKind.BreakStatement:
return visitNode(cbNode, (<BreakOrContinueStatement>node).label);
case SyntaxKind.ReturnStatement:
return visitNode(cbNode, (<ReturnStatement>node).expression);
case SyntaxKind.WithStatement:
return visitNode(cbNode, (<WithStatement>node).expression) ||
visitNode(cbNode, (<WithStatement>node).statement);
case SyntaxKind.SwitchStatement:
return visitNode(cbNode, (<SwitchStatement>node).expression) ||
visitNode(cbNode, (<SwitchStatement>node).caseBlock);
case SyntaxKind.CaseBlock:
return visitNodes(cbNodes, (<CaseBlock>node).clauses);
case SyntaxKind.CaseClause:
return visitNode(cbNode, (<CaseClause>node).expression) ||
visitNodes(cbNodes, (<CaseClause>node).statements);
case SyntaxKind.DefaultClause:
return visitNodes(cbNodes, (<DefaultClause>node).statements);
case SyntaxKind.LabeledStatement:
return visitNode(cbNode, (<LabeledStatement>node).label) ||
visitNode(cbNode, (<LabeledStatement>node).statement);
case SyntaxKind.ThrowStatement:
return visitNode(cbNode, (<ThrowStatement>node).expression);
case SyntaxKind.TryStatement:
return visitNode(cbNode, (<TryStatement>node).tryBlock) ||
visitNode(cbNode, (<TryStatement>node).catchClause) ||
visitNode(cbNode, (<TryStatement>node).finallyBlock);
case SyntaxKind.CatchClause:
return visitNode(cbNode, (<CatchClause>node).variableDeclaration) ||
visitNode(cbNode, (<CatchClause>node).block);
case SyntaxKind.Decorator:
return visitNode(cbNode, (<Decorator>node).expression);
case SyntaxKind.ClassDeclaration:
case SyntaxKind.ClassExpression:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ClassLikeDeclaration>node).name) ||
visitNodes(cbNodes, (<ClassLikeDeclaration>node).typeParameters) ||
visitNodes(cbNodes, (<ClassLikeDeclaration>node).heritageClauses) ||
visitNodes(cbNodes, (<ClassLikeDeclaration>node).members);
case SyntaxKind.InterfaceDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<InterfaceDeclaration>node).name) ||
visitNodes(cbNodes, (<InterfaceDeclaration>node).typeParameters) ||
visitNodes(cbNodes, (<ClassDeclaration>node).heritageClauses) ||
visitNodes(cbNodes, (<InterfaceDeclaration>node).members);
case SyntaxKind.TypeAliasDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<TypeAliasDeclaration>node).name) ||
visitNode(cbNode, (<TypeAliasDeclaration>node).type);
case SyntaxKind.EnumDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<EnumDeclaration>node).name) ||
visitNodes(cbNodes, (<EnumDeclaration>node).members);
case SyntaxKind.EnumMember:
return visitNode(cbNode, (<EnumMember>node).name) ||
visitNode(cbNode, (<EnumMember>node).initializer);
case SyntaxKind.ModuleDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ModuleDeclaration>node).name) ||
visitNode(cbNode, (<ModuleDeclaration>node).body);
case SyntaxKind.ImportEqualsDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ImportEqualsDeclaration>node).name) ||
visitNode(cbNode, (<ImportEqualsDeclaration>node).moduleReference);
case SyntaxKind.ImportDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ImportDeclaration>node).importClause) ||
visitNode(cbNode, (<ImportDeclaration>node).moduleSpecifier);
case SyntaxKind.ImportClause:
return visitNode(cbNode, (<ImportClause>node).name) ||
visitNode(cbNode, (<ImportClause>node).namedBindings);
case SyntaxKind.NamespaceImport:
return visitNode(cbNode, (<NamespaceImport>node).name);
case SyntaxKind.NamedImports:
case SyntaxKind.NamedExports:
return visitNodes(cbNodes, (<NamedImportsOrExports>node).elements);
case SyntaxKind.ExportDeclaration:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ExportDeclaration>node).exportClause) ||
visitNode(cbNode, (<ExportDeclaration>node).moduleSpecifier);
case SyntaxKind.ImportSpecifier:
case SyntaxKind.ExportSpecifier:
return visitNode(cbNode, (<ImportOrExportSpecifier>node).propertyName) ||
visitNode(cbNode, (<ImportOrExportSpecifier>node).name);
case SyntaxKind.ExportAssignment:
return visitNodes(cbNodes, node.decorators) ||
visitNodes(cbNodes, node.modifiers) ||
visitNode(cbNode, (<ExportAssignment>node).expression);
case SyntaxKind.TemplateExpression:
return visitNode(cbNode, (<TemplateExpression>node).head) || visitNodes(cbNodes, (<TemplateExpression>node).templateSpans);
case SyntaxKind.TemplateSpan:
return visitNode(cbNode, (<TemplateSpan>node).expression) || visitNode(cbNode, (<TemplateSpan>node).literal);
case SyntaxKind.ComputedPropertyName:
return visitNode(cbNode, (<ComputedPropertyName>node).expression);
case SyntaxKind.HeritageClause:
return visitNodes(cbNodes, (<HeritageClause>node).types);
case SyntaxKind.HeritageClauseElement:
return visitNode(cbNode, (<HeritageClauseElement>node).expression) ||
visitNodes(cbNodes, (<HeritageClauseElement>node).typeArguments);
case SyntaxKind.ExternalModuleReference:
return visitNode(cbNode, (<ExternalModuleReference>node).expression);
case SyntaxKind.MissingDeclaration:
return visitNodes(cbNodes, node.decorators);
}
}
export function createSourceFile(fileName: string, sourceText: string, languageVersion: ScriptTarget, setParentNodes = false): SourceFile {
let start = new Date().getTime();
let result = Parser.parseSourceFile(fileName, sourceText, languageVersion, /*syntaxCursor*/ undefined, setParentNodes);
parseTime += new Date().getTime() - start;
return result;
}
// Produces a new SourceFile for the 'newText' provided. The 'textChangeRange' parameter
// indicates what changed between the 'text' that this SourceFile has and the 'newText'.
// The SourceFile will be created with the compiler attempting to reuse as many nodes from
// this file as possible.
//
// Note: this function mutates nodes from this SourceFile. That means any existing nodes
// from this SourceFile that are being held onto may change as a result (including
// becoming detached from any SourceFile). It is recommended that this SourceFile not
// be used once 'update' is called on it.
export function updateSourceFile(sourceFile: SourceFile, newText: string, textChangeRange: TextChangeRange, aggressiveChecks?: boolean): SourceFile {
return IncrementalParser.updateSourceFile(sourceFile, newText, textChangeRange, aggressiveChecks);
}
// Implement the parser as a singleton module. We do this for perf reasons because creating
// parser instances can actually be expensive enough to impact us on projects with many source
// files.
module Parser {
// Share a single scanner across all calls to parse a source file. This helps speed things
// up by avoiding the cost of creating/compiling scanners over and over again.
const scanner = createScanner(ScriptTarget.Latest, /*skipTrivia:*/ true);
const disallowInAndDecoratorContext = ParserContextFlags.DisallowIn | ParserContextFlags.Decorator;
let sourceFile: SourceFile;
let syntaxCursor: IncrementalParser.SyntaxCursor;
let token: SyntaxKind;
let sourceText: string;
let nodeCount: number;
let identifiers: Map<string>;
let identifierCount: number;
let parsingContext: ParsingContext;
// Flags that dictate what parsing context we're in. For example:
// Whether or not we are in strict parsing mode. All that changes in strict parsing mode is
// that some tokens that would be considered identifiers may be considered keywords.
//
// When adding more parser context flags, consider which is the more common case that the
// flag will be in. This should be the 'false' state for that flag. The reason for this is
// that we don't store data in our nodes unless the value is in the *non-default* state. So,
// for example, more often than code 'allows-in' (or doesn't 'disallow-in'). We opt for
// 'disallow-in' set to 'false'. Otherwise, if we had 'allowsIn' set to 'true', then almost
// all nodes would need extra state on them to store this info.
//
// Note: 'allowIn' and 'allowYield' track 1:1 with the [in] and [yield] concepts in the ES6
// grammar specification.
//
// An important thing about these context concepts. By default they are effectively inherited
// while parsing through every grammar production. i.e. if you don't change them, then when
// you parse a sub-production, it will have the same context values as the parent production.
// This is great most of the time. After all, consider all the 'expression' grammar productions
// and how nearly all of them pass along the 'in' and 'yield' context values:
//
// EqualityExpression[In, Yield] :
// RelationalExpression[?In, ?Yield]
// EqualityExpression[?In, ?Yield] == RelationalExpression[?In, ?Yield]
// EqualityExpression[?In, ?Yield] != RelationalExpression[?In, ?Yield]
// EqualityExpression[?In, ?Yield] === RelationalExpression[?In, ?Yield]
// EqualityExpression[?In, ?Yield] !== RelationalExpression[?In, ?Yield]
//
// Where you have to be careful is then understanding what the points are in the grammar
// where the values are *not* passed along. For example:
//
// SingleNameBinding[Yield,GeneratorParameter]
// [+GeneratorParameter]BindingIdentifier[Yield] Initializer[In]opt
// [~GeneratorParameter]BindingIdentifier[?Yield]Initializer[In, ?Yield]opt
//
// Here this is saying that if the GeneratorParameter context flag is set, that we should
// explicitly set the 'yield' context flag to false before calling into the BindingIdentifier
// and we should explicitly unset the 'yield' context flag before calling into the Initializer.
// production. Conversely, if the GeneratorParameter context flag is not set, then we
// should leave the 'yield' context flag alone.
//
// Getting this all correct is tricky and requires careful reading of the grammar to
// understand when these values should be changed versus when they should be inherited.
//
// Note: it should not be necessary to save/restore these flags during speculative/lookahead
// parsing. These context flags are naturally stored and restored through normal recursive
// descent parsing and unwinding.
let contextFlags: ParserContextFlags = 0;
// Whether or not we've had a parse error since creating the last AST node. If we have
// encountered an error, it will be stored on the next AST node we create. Parse errors
// can be broken down into three categories:
//
// 1) An error that occurred during scanning. For example, an unterminated literal, or a
// character that was completely not understood.
//
// 2) A token was expected, but was not present. This type of error is commonly produced
// by the 'parseExpected' function.
//
// 3) A token was present that no parsing function was able to consume. This type of error
// only occurs in the 'abortParsingListOrMoveToNextToken' function when the parser
// decides to skip the token.
//
// In all of these cases, we want to mark the next node as having had an error before it.
// With this mark, we can know in incremental settings if this node can be reused, or if
// we have to reparse it. If we don't keep this information around, we may just reuse the
// node. in that event we would then not produce the same errors as we did before, causing
// significant confusion problems.
//
// Note: it is necessary that this value be saved/restored during speculative/lookahead
// parsing. During lookahead parsing, we will often create a node. That node will have
// this value attached, and then this value will be set back to 'false'. If we decide to
// rewind, we must get back to the same value we had prior to the lookahead.
//
// Note: any errors at the end of the file that do not precede a regular node, should get
// attached to the EOF token.
let parseErrorBeforeNextFinishedNode: boolean = false;
export function parseSourceFile(fileName: string, _sourceText: string, languageVersion: ScriptTarget, _syntaxCursor: IncrementalParser.SyntaxCursor, setParentNodes?: boolean): SourceFile {
sourceText = _sourceText;
syntaxCursor = _syntaxCursor;
parsingContext = 0;
identifiers = {};
identifierCount = 0;
nodeCount = 0;
contextFlags = 0;
parseErrorBeforeNextFinishedNode = false;
createSourceFile(fileName, languageVersion);
// Initialize and prime the scanner before parsing the source elements.
scanner.setText(sourceText);
scanner.setOnError(scanError);
scanner.setScriptTarget(languageVersion);
token = nextToken();
processReferenceComments(sourceFile);
sourceFile.statements = parseList(ParsingContext.SourceElements, /*checkForStrictMode*/ true, parseSourceElement);
Debug.assert(token === SyntaxKind.EndOfFileToken);
sourceFile.endOfFileToken = parseTokenNode();
setExternalModuleIndicator(sourceFile);
sourceFile.nodeCount = nodeCount;
sourceFile.identifierCount = identifierCount;
sourceFile.identifiers = identifiers;
if (setParentNodes) {
fixupParentReferences(sourceFile);
}
syntaxCursor = undefined;
// Clear out the text the scanner is pointing at, so it doesn't keep anything alive unnecessarily.
scanner.setText("");
scanner.setOnError(undefined);
let result = sourceFile;
// Clear any data. We don't want to accidently hold onto it for too long.
sourceFile = undefined;
identifiers = undefined;
syntaxCursor = undefined;
sourceText = undefined;
return result;
}
function fixupParentReferences(sourceFile: SourceFile) {
// normally parent references are set during binding. However, for clients that only need
// a syntax tree, and no semantic features, then the binding process is an unnecessary
// overhead. This functions allows us to set all the parents, without all the expense of
// binding.
let parent: Node = sourceFile;
forEachChild(sourceFile, visitNode);
return;
function visitNode(n: Node): void {
// walk down setting parents that differ from the parent we think it should be. This
// allows us to quickly bail out of setting parents for subtrees during incremental
// parsing
if (n.parent !== parent) {
n.parent = parent;
let saveParent = parent;
parent = n;
forEachChild(n, visitNode);
parent = saveParent;
}
}
}
function createSourceFile(fileName: string, languageVersion: ScriptTarget) {
sourceFile = <SourceFile>createNode(SyntaxKind.SourceFile, /*pos*/ 0);
sourceFile.pos = 0;
sourceFile.end = sourceText.length;
sourceFile.text = sourceText;
sourceFile.parseDiagnostics = [];
sourceFile.bindDiagnostics = [];
sourceFile.languageVersion = languageVersion;
sourceFile.fileName = normalizePath(fileName);
sourceFile.flags = fileExtensionIs(sourceFile.fileName, ".d.ts") ? NodeFlags.DeclarationFile : 0;
}
function setContextFlag(val: Boolean, flag: ParserContextFlags) {
if (val) {
contextFlags |= flag;
}
else {
contextFlags &= ~flag;
}
}
function setStrictModeContext(val: boolean) {
setContextFlag(val, ParserContextFlags.StrictMode);
}
function setDisallowInContext(val: boolean) {
setContextFlag(val, ParserContextFlags.DisallowIn);
}
function setYieldContext(val: boolean) {
setContextFlag(val, ParserContextFlags.Yield);
}
function setGeneratorParameterContext(val: boolean) {
setContextFlag(val, ParserContextFlags.GeneratorParameter);
}
function setDecoratorContext(val: boolean) {
setContextFlag(val, ParserContextFlags.Decorator);
}
function doOutsideOfContext<T>(flags: ParserContextFlags, func: () => T): T {
let currentContextFlags = contextFlags & flags;
if (currentContextFlags) {
setContextFlag(false, currentContextFlags);
let result = func();
setContextFlag(true, currentContextFlags);
return result;
}
// no need to do anything special as we are not in any of the requested contexts
return func();
}
function allowInAnd<T>(func: () => T): T {
if (contextFlags & ParserContextFlags.DisallowIn) {
setDisallowInContext(false);
let result = func();
setDisallowInContext(true);
return result;
}
// no need to do anything special if 'in' is already allowed.
return func();
}
function disallowInAnd<T>(func: () => T): T {
if (contextFlags & ParserContextFlags.DisallowIn) {
// no need to do anything special if 'in' is already disallowed.
return func();
}
setDisallowInContext(true);
let result = func();
setDisallowInContext(false);
return result;
}
function doInYieldContext<T>(func: () => T): T {
if (contextFlags & ParserContextFlags.Yield) {
// no need to do anything special if we're already in the [Yield] context.
return func();
}
setYieldContext(true);
let result = func();
setYieldContext(false);
return result;
}
function doOutsideOfYieldContext<T>(func: () => T): T {
if (contextFlags & ParserContextFlags.Yield) {
setYieldContext(false);
let result = func();
setYieldContext(true);
return result;
}
// no need to do anything special if we're not in the [Yield] context.
return func();
}
function doInDecoratorContext<T>(func: () => T): T {
if (contextFlags & ParserContextFlags.Decorator) {
// no need to do anything special if we're already in the [Decorator] context.
return func();
}
setDecoratorContext(true);
let result = func();
setDecoratorContext(false);
return result;
}
function inYieldContext() {
return (contextFlags & ParserContextFlags.Yield) !== 0;
}
function inStrictModeContext() {
return (contextFlags & ParserContextFlags.StrictMode) !== 0;
}
function inGeneratorParameterContext() {
return (contextFlags & ParserContextFlags.GeneratorParameter) !== 0;
}
function inDisallowInContext() {
return (contextFlags & ParserContextFlags.DisallowIn) !== 0;
}
function inDecoratorContext() {
return (contextFlags & ParserContextFlags.Decorator) !== 0;
}
function parseErrorAtCurrentToken(message: DiagnosticMessage, arg0?: any): void {
let start = scanner.getTokenPos();
let length = scanner.getTextPos() - start;
parseErrorAtPosition(start, length, message, arg0);
}
function parseErrorAtPosition(start: number, length: number, message: DiagnosticMessage, arg0?: any): void {
// Don't report another error if it would just be at the same position as the last error.
let lastError = lastOrUndefined(sourceFile.parseDiagnostics);
if (!lastError || start !== lastError.start) {
sourceFile.parseDiagnostics.push(createFileDiagnostic(sourceFile, start, length, message, arg0));
}
// Mark that we've encountered an error. We'll set an appropriate bit on the next
// node we finish so that it can't be reused incrementally.
parseErrorBeforeNextFinishedNode = true;
}
function scanError(message: DiagnosticMessage, length?: number) {
let pos = scanner.getTextPos();
parseErrorAtPosition(pos, length || 0, message);
}
function getNodePos(): number {
return scanner.getStartPos();
}
function getNodeEnd(): number {
return scanner.getStartPos();
}
function nextToken(): SyntaxKind {
return token = scanner.scan();
}
function getTokenPos(pos: number): number {
return skipTrivia(sourceText, pos);
}
function reScanGreaterToken(): SyntaxKind {
return token = scanner.reScanGreaterToken();
}
function reScanSlashToken(): SyntaxKind {
return token = scanner.reScanSlashToken();
}
function reScanTemplateToken(): SyntaxKind {
return token = scanner.reScanTemplateToken();
}
function speculationHelper<T>(callback: () => T, isLookAhead: boolean): T {
// Keep track of the state we'll need to rollback to if lookahead fails (or if the
// caller asked us to always reset our state).
let saveToken = token;
let saveParseDiagnosticsLength = sourceFile.parseDiagnostics.length;
let saveParseErrorBeforeNextFinishedNode = parseErrorBeforeNextFinishedNode;
// Note: it is not actually necessary to save/restore the context flags here. That's
// because the saving/restorating of these flags happens naturally through the recursive
// descent nature of our parser. However, we still store this here just so we can
// assert that that invariant holds.
let saveContextFlags = contextFlags;
// If we're only looking ahead, then tell the scanner to only lookahead as well.
// Otherwise, if we're actually speculatively parsing, then tell the scanner to do the
// same.
let result = isLookAhead
? scanner.lookAhead(callback)
: scanner.tryScan(callback);
Debug.assert(saveContextFlags === contextFlags);
// If our callback returned something 'falsy' or we're just looking ahead,
// then unconditionally restore us to where we were.
if (!result || isLookAhead) {
token = saveToken;
sourceFile.parseDiagnostics.length = saveParseDiagnosticsLength;
parseErrorBeforeNextFinishedNode = saveParseErrorBeforeNextFinishedNode;
}
return result;
}
// Invokes the provided callback then unconditionally restores the parser to the state it
// was in immediately prior to invoking the callback. The result of invoking the callback
// is returned from this function.
function lookAhead<T>(callback: () => T): T {
return speculationHelper(callback, /*isLookAhead:*/ true);
}
// Invokes the provided callback. If the callback returns something falsy, then it restores
// the parser to the state it was in immediately prior to invoking the callback. If the
// callback returns something truthy, then the parser state is not rolled back. The result
// of invoking the callback is returned from this function.
function tryParse<T>(callback: () => T): T {
return speculationHelper(callback, /*isLookAhead:*/ false);
}
// Ignore strict mode flag because we will report an error in type checker instead.
function isIdentifier(): boolean {
if (token === SyntaxKind.Identifier) {
return true;
}
// If we have a 'yield' keyword, and we're in the [yield] context, then 'yield' is
// considered a keyword and is not an identifier.
if (token === SyntaxKind.YieldKeyword && inYieldContext()) {
return false;
}
return token > SyntaxKind.LastReservedWord;
}
function parseExpected(kind: SyntaxKind, diagnosticMessage?: DiagnosticMessage): boolean {
if (token === kind) {
nextToken();
return true;
}
// Report specific message if provided with one. Otherwise, report generic fallback message.
if (diagnosticMessage) {
parseErrorAtCurrentToken(diagnosticMessage);
}
else {
parseErrorAtCurrentToken(Diagnostics._0_expected, tokenToString(kind));
}
return false;
}
function parseOptional(t: SyntaxKind): boolean {
if (token === t) {
nextToken();
return true;
}
return false;
}
function parseOptionalToken(t: SyntaxKind): Node {
if (token === t) {
return parseTokenNode();
}
return undefined;
}
function parseExpectedToken(t: SyntaxKind, reportAtCurrentPosition: boolean, diagnosticMessage: DiagnosticMessage, arg0?: any): Node {
return parseOptionalToken(t) ||
createMissingNode(t, reportAtCurrentPosition, diagnosticMessage, arg0);
}
function parseTokenNode<T extends Node>(): T {
let node = <T>createNode(token);
nextToken();
return finishNode(node);
}
function canParseSemicolon() {
// If there's a real semicolon, then we can always parse it out.
if (token === SyntaxKind.SemicolonToken) {
return true;
}
// We can parse out an optional semicolon in ASI cases in the following cases.
return token === SyntaxKind.CloseBraceToken || token === SyntaxKind.EndOfFileToken || scanner.hasPrecedingLineBreak();
}
function parseSemicolon(): boolean {
if (canParseSemicolon()) {
if (token === SyntaxKind.SemicolonToken) {
// consume the semicolon if it was explicitly provided.
nextToken();
}
return true;
}
else {
return parseExpected(SyntaxKind.SemicolonToken);
}
}
function createNode(kind: SyntaxKind, pos?: number): Node {
nodeCount++;
let node = new (nodeConstructors[kind] || (nodeConstructors[kind] = objectAllocator.getNodeConstructor(kind)))();
if (!(pos >= 0)) {
pos = scanner.getStartPos();
}
node.pos = pos;
node.end = pos;
return node;
}
function finishNode<T extends Node>(node: T): T {
node.end = scanner.getStartPos();
if (contextFlags) {
node.parserContextFlags = contextFlags;
}
// Keep track on the node if we encountered an error while parsing it. If we did, then
// we cannot reuse the node incrementally. Once we've marked this node, clear out the
// flag so that we don't mark any subsequent nodes.
if (parseErrorBeforeNextFinishedNode) {
parseErrorBeforeNextFinishedNode = false;
node.parserContextFlags |= ParserContextFlags.ThisNodeHasError;
}
return node;
}
function createMissingNode(kind: SyntaxKind, reportAtCurrentPosition: boolean, diagnosticMessage: DiagnosticMessage, arg0?: any): Node {
if (reportAtCurrentPosition) {
parseErrorAtPosition(scanner.getStartPos(), 0, diagnosticMessage, arg0);
}
else {
parseErrorAtCurrentToken(diagnosticMessage, arg0);
}
let result = createNode(kind, scanner.getStartPos());
(<Identifier>result).text = "";
return finishNode(result);
}
function internIdentifier(text: string): string {
text = escapeIdentifier(text);
return hasProperty(identifiers, text) ? identifiers[text] : (identifiers[text] = text);
}
// An identifier that starts with two underscores has an extra underscore character prepended to it to avoid issues
// with magic property names like '__proto__'. The 'identifiers' object is used to share a single string instance for
// each identifier in order to reduce memory consumption.
function createIdentifier(isIdentifier: boolean, diagnosticMessage?: DiagnosticMessage): Identifier {
identifierCount++;
if (isIdentifier) {
let node = <Identifier>createNode(SyntaxKind.Identifier);
// Store original token kind if it is not just an Identifier so we can report appropriate error later in type checker
if (token !== SyntaxKind.Identifier) {
node.originalKeywordKind = token;
}
node.text = internIdentifier(scanner.getTokenValue());
nextToken();
return finishNode(node);
}
return <Identifier>createMissingNode(SyntaxKind.Identifier, /*reportAtCurrentPosition:*/ false, diagnosticMessage || Diagnostics.Identifier_expected);
}
function parseIdentifier(diagnosticMessage?: DiagnosticMessage): Identifier {
return createIdentifier(isIdentifier(), diagnosticMessage);
}
function parseIdentifierName(): Identifier {
return createIdentifier(isIdentifierOrKeyword());
}
function isLiteralPropertyName(): boolean {
return isIdentifierOrKeyword() ||
token === SyntaxKind.StringLiteral ||
token === SyntaxKind.NumericLiteral;
}
function parsePropertyName(): DeclarationName {
if (token === SyntaxKind.StringLiteral || token === SyntaxKind.NumericLiteral) {
return parseLiteralNode(/*internName:*/ true);
}
if (token === SyntaxKind.OpenBracketToken) {
return parseComputedPropertyName();
}
return parseIdentifierName();
}
function parseComputedPropertyName(): ComputedPropertyName {
// PropertyName[Yield,GeneratorParameter] :
// LiteralPropertyName
// [+GeneratorParameter] ComputedPropertyName
// [~GeneratorParameter] ComputedPropertyName[?Yield]
//
// ComputedPropertyName[Yield] :
// [ AssignmentExpression[In, ?Yield] ]
//
let node = <ComputedPropertyName>createNode(SyntaxKind.ComputedPropertyName);
parseExpected(SyntaxKind.OpenBracketToken);
// We parse any expression (including a comma expression). But the grammar
// says that only an assignment expression is allowed, so the grammar checker
// will error if it sees a comma expression.
let yieldContext = inYieldContext();
if (inGeneratorParameterContext()) {
setYieldContext(false);
}
node.expression = allowInAnd(parseExpression);
if (inGeneratorParameterContext()) {
setYieldContext(yieldContext);
}
parseExpected(SyntaxKind.CloseBracketToken);
return finishNode(node);
}
function parseContextualModifier(t: SyntaxKind): boolean {
return token === t && tryParse(nextTokenCanFollowModifier);
}
function nextTokenCanFollowModifier() {
nextToken();
return canFollowModifier();
}
function parseAnyContextualModifier(): boolean {
return isModifier(token) && tryParse(nextTokenCanFollowContextualModifier);
}
function nextTokenCanFollowContextualModifier() {
if (token === SyntaxKind.ConstKeyword) {
// 'const' is only a modifier if followed by 'enum'.
return nextToken() === SyntaxKind.EnumKeyword;
}
if (token === SyntaxKind.ExportKeyword) {
nextToken();
if (token === SyntaxKind.DefaultKeyword) {
return lookAhead(nextTokenIsClassOrFunction);
}
return token !== SyntaxKind.AsteriskToken && token !== SyntaxKind.OpenBraceToken && canFollowModifier();
}
if (token === SyntaxKind.DefaultKeyword) {
return nextTokenIsClassOrFunction();
}
nextToken();
return canFollowModifier();
}
function canFollowModifier(): boolean {
return token === SyntaxKind.OpenBracketToken
|| token === SyntaxKind.OpenBraceToken
|| token === SyntaxKind.AsteriskToken
|| isLiteralPropertyName();
}
function nextTokenIsClassOrFunction(): boolean {
nextToken();
return token === SyntaxKind.ClassKeyword || token === SyntaxKind.FunctionKeyword;
}
// True if positioned at the start of a list element
function isListElement(parsingContext: ParsingContext, inErrorRecovery: boolean): boolean {