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Copy pathparser.ts
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3183 lines (2873 loc) · 156 KB
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/// <reference path="sys.ts"/>
/// <reference path="types.ts"/>
/// <reference path="core.ts"/>
/// <reference path="scanner.ts"/>
module ts {
var nodeConstructors = new Array<new () => Node>(SyntaxKind.Count);
export function getNodeConstructor(kind: SyntaxKind): new () => Node {
return nodeConstructors[kind] || (nodeConstructors[kind] = objectAllocator.getNodeConstructor(kind));
}
function createRootNode(kind: SyntaxKind, pos: number, end: number, flags: NodeFlags): Node {
var node = new (getNodeConstructor(kind))();
node.pos = pos;
node.end = end;
node.flags = flags;
return node;
}
var moduleExtensions = [".d.ts", ".ts", ".js"];
interface ReferenceComments {
referencedFiles: FileReference[];
amdDependencies: string[];
}
export function getModuleNameFromFilename(filename: string) {
for (var i = 0; i < moduleExtensions.length; i++) {
var ext = moduleExtensions[i];
var len = filename.length - ext.length;
if (len > 0 && filename.substr(len) === ext) return filename.substr(0, len);
}
return filename;
}
export function getSourceFileOfNode(node: Node): SourceFile {
while (node && node.kind !== SyntaxKind.SourceFile) node = node.parent;
return <SourceFile>node;
}
// This is a useful function for debugging purposes.
export function nodePosToString(node: Node): string {
var file = getSourceFileOfNode(node);
var loc = file.getLineAndCharacterFromPosition(node.pos);
return file.filename + "(" + loc.line + "," + loc.character + ")";
}
export function getStartPosOfNode(node: Node): number {
return node.pos;
}
export function getTokenPosOfNode(node: Node): number {
return skipTrivia(getSourceFileOfNode(node).text, node.pos);
}
export function getSourceTextOfNode(node: Node): string {
var text = getSourceFileOfNode(node).text;
return text.substring(skipTrivia(text, node.pos), node.end);
}
// Add an extra underscore to identifiers that start with two underscores to avoid issues with magic names like '__proto__'
export function escapeIdentifier(identifier: string): string {
return identifier.charCodeAt(0) === CharacterCodes._ && identifier.charCodeAt(1) === CharacterCodes._ ? "_" + identifier : identifier;
}
// Return display name of an identifier
export function identifierToString(identifier: Identifier) {
return identifier.kind === SyntaxKind.Missing ? "(Missing)" : getSourceTextOfNode(identifier);
}
export function createDiagnosticForNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): Diagnostic {
var file = getSourceFileOfNode(node);
var start = skipTrivia(file.text, node.pos);
var length = node.end - start;
return createFileDiagnostic(file, start, length, message, arg0, arg1, arg2);
}
export function createDiagnosticForNodeFromMessageChain(node: Node, messageChain: DiagnosticMessageChain): Diagnostic {
var file = getSourceFileOfNode(node);
var start = skipTrivia(file.text, node.pos);
var length = node.end - start;
return flattenDiagnosticChain(file, start, length, messageChain);
}
// 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, cbNodes?: (nodes: Node[]) => T): T {
function child(node: Node): T {
if (node) return cbNode(node);
}
function children(nodes: Node[]) {
if (nodes) {
if (cbNodes) return cbNodes(nodes);
var result: T;
for (var i = 0, len = nodes.length; i < len; i++) {
if (result = cbNode(nodes[i])) break;
}
return result;
}
}
if (!node) return;
switch (node.kind) {
case SyntaxKind.QualifiedName:
return child((<QualifiedName>node).left) ||
child((<QualifiedName>node).right);
case SyntaxKind.TypeParameter:
return child((<TypeParameterDeclaration>node).name) ||
child((<TypeParameterDeclaration>node).constraint);
case SyntaxKind.Parameter:
return child((<ParameterDeclaration>node).name) ||
child((<ParameterDeclaration>node).type) ||
child((<ParameterDeclaration>node).initializer);
case SyntaxKind.Property:
case SyntaxKind.PropertyAssignment:
return child((<PropertyDeclaration>node).name) ||
child((<PropertyDeclaration>node).type) ||
child((<PropertyDeclaration>node).initializer);
case SyntaxKind.CallSignature:
case SyntaxKind.ConstructSignature:
case SyntaxKind.IndexSignature:
return children((<SignatureDeclaration>node).typeParameters) ||
children((<SignatureDeclaration>node).parameters) ||
child((<SignatureDeclaration>node).type);
case SyntaxKind.Method:
case SyntaxKind.Constructor:
case SyntaxKind.GetAccessor:
case SyntaxKind.SetAccessor:
case SyntaxKind.FunctionExpression:
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ArrowFunction:
return child((<FunctionDeclaration>node).name) ||
children((<FunctionDeclaration>node).typeParameters) ||
children((<FunctionDeclaration>node).parameters) ||
child((<FunctionDeclaration>node).type) ||
child((<FunctionDeclaration>node).body);
case SyntaxKind.TypeReference:
return child((<TypeReferenceNode>node).typeName) ||
children((<TypeReferenceNode>node).typeArguments);
case SyntaxKind.TypeQuery:
return child((<TypeQueryNode>node).exprName);
case SyntaxKind.TypeLiteral:
return children((<TypeLiteralNode>node).members);
case SyntaxKind.ArrayType:
return child((<ArrayTypeNode>node).elementType);
case SyntaxKind.ArrayLiteral:
return children((<ArrayLiteral>node).elements);
case SyntaxKind.ObjectLiteral:
return children((<ObjectLiteral>node).properties);
case SyntaxKind.PropertyAccess:
return child((<PropertyAccess>node).left) ||
child((<PropertyAccess>node).right);
case SyntaxKind.IndexedAccess:
return child((<IndexedAccess>node).object) ||
child((<IndexedAccess>node).index);
case SyntaxKind.CallExpression:
case SyntaxKind.NewExpression:
return child((<CallExpression>node).func) ||
children((<CallExpression>node).typeArguments) ||
children((<CallExpression>node).arguments);
case SyntaxKind.TypeAssertion:
return child((<TypeAssertion>node).type) ||
child((<TypeAssertion>node).operand);
case SyntaxKind.ParenExpression:
return child((<ParenExpression>node).expression);
case SyntaxKind.PrefixOperator:
case SyntaxKind.PostfixOperator:
return child((<UnaryExpression>node).operand);
case SyntaxKind.BinaryExpression:
return child((<BinaryExpression>node).left) ||
child((<BinaryExpression>node).right);
case SyntaxKind.ConditionalExpression:
return child((<ConditionalExpression>node).condition) ||
child((<ConditionalExpression>node).whenTrue) ||
child((<ConditionalExpression>node).whenFalse);
case SyntaxKind.Block:
case SyntaxKind.TryBlock:
case SyntaxKind.FinallyBlock:
case SyntaxKind.FunctionBlock:
case SyntaxKind.ModuleBlock:
case SyntaxKind.SourceFile:
return children((<Block>node).statements);
case SyntaxKind.VariableStatement:
return children((<VariableStatement>node).declarations);
case SyntaxKind.ExpressionStatement:
return child((<ExpressionStatement>node).expression);
case SyntaxKind.IfStatement:
return child((<IfStatement>node).expression) ||
child((<IfStatement>node).thenStatement) ||
child((<IfStatement>node).elseStatement);
case SyntaxKind.DoStatement:
return child((<DoStatement>node).statement) ||
child((<DoStatement>node).expression);
case SyntaxKind.WhileStatement:
return child((<WhileStatement>node).expression) ||
child((<WhileStatement>node).statement);
case SyntaxKind.ForStatement:
return children((<ForStatement>node).declarations) ||
child((<ForStatement>node).initializer) ||
child((<ForStatement>node).condition) ||
child((<ForStatement>node).iterator) ||
child((<ForStatement>node).statement);
case SyntaxKind.ForInStatement:
return child((<ForInStatement>node).declaration) ||
child((<ForInStatement>node).variable) ||
child((<ForInStatement>node).expression) ||
child((<ForInStatement>node).statement);
case SyntaxKind.ContinueStatement:
case SyntaxKind.BreakStatement:
return child((<BreakOrContinueStatement>node).label);
case SyntaxKind.ReturnStatement:
return child((<ReturnStatement>node).expression);
case SyntaxKind.WithStatement:
return child((<WithStatement>node).expression) ||
child((<WithStatement>node).statement);
case SyntaxKind.SwitchStatement:
return child((<SwitchStatement>node).expression) ||
children((<SwitchStatement>node).clauses);
case SyntaxKind.CaseClause:
case SyntaxKind.DefaultClause:
return child((<CaseOrDefaultClause>node).expression) ||
children((<CaseOrDefaultClause>node).statements);
case SyntaxKind.LabelledStatement:
return child((<LabelledStatement>node).label) ||
child((<LabelledStatement>node).statement);
case SyntaxKind.ThrowStatement:
return child((<ThrowStatement>node).expression);
case SyntaxKind.TryStatement:
return child((<TryStatement>node).tryBlock) ||
child((<TryStatement>node).catchBlock) ||
child((<TryStatement>node).finallyBlock);
case SyntaxKind.CatchBlock:
return child((<CatchBlock>node).variable) ||
children((<CatchBlock>node).statements);
case SyntaxKind.VariableDeclaration:
return child((<VariableDeclaration>node).name) ||
child((<VariableDeclaration>node).type) ||
child((<VariableDeclaration>node).initializer);
case SyntaxKind.ClassDeclaration:
return child((<ClassDeclaration>node).name) ||
children((<ClassDeclaration>node).typeParameters) ||
child((<ClassDeclaration>node).baseType) ||
children((<ClassDeclaration>node).implementedTypes) ||
children((<ClassDeclaration>node).members);
case SyntaxKind.InterfaceDeclaration:
return child((<InterfaceDeclaration>node).name) ||
children((<InterfaceDeclaration>node).typeParameters) ||
children((<InterfaceDeclaration>node).baseTypes) ||
children((<InterfaceDeclaration>node).members);
case SyntaxKind.EnumDeclaration:
return child((<EnumDeclaration>node).name) ||
children((<EnumDeclaration>node).members);
case SyntaxKind.EnumMember:
return child((<EnumMember>node).name) ||
child((<EnumMember>node).initializer);
case SyntaxKind.ModuleDeclaration:
return child((<ModuleDeclaration>node).name) ||
child((<ModuleDeclaration>node).body);
case SyntaxKind.ImportDeclaration:
return child((<ImportDeclaration>node).name) ||
child((<ImportDeclaration>node).entityName) ||
child((<ImportDeclaration>node).externalModuleName);
case SyntaxKind.ExportAssignment:
return child((<ExportAssignment>node).exportName);
}
}
export function hasRestParameters(s: SignatureDeclaration): boolean {
return s.parameters.length > 0 && (s.parameters[s.parameters.length - 1].flags & NodeFlags.Rest) !== 0;
}
enum ParsingContext {
SourceElements, // Elements in source file
ModuleElements, // Elements in module declaration
BlockStatements, // Statements in block
SwitchClauses, // Clauses in switch statement
SwitchClauseStatements, // Statements in switch clause
TypeMembers, // Members in interface or type literal
ClassMembers, // Members in class declaration
EnumMembers, // Members in enum declaration
BaseTypeReferences, // Type references in extends or implements clause
VariableDeclarations, // Variable declarations in variable statement
ArgumentExpressions, // Expressions in argument list
ObjectLiteralMembers, // Members in object literal
ArrayLiteralMembers, // Members in array literal
Parameters, // Parameters in parameter list
TypeParameters, // Type parameters in type parameter list
TypeArguments, // Type arguments in type argument list
Count // Number of parsing contexts
}
enum Tristate {
False,
True,
Unknown
}
function parsingContextErrors(context: ParsingContext): DiagnosticMessage {
switch (context) {
case ParsingContext.SourceElements: return Diagnostics.Declaration_or_statement_expected;
case ParsingContext.ModuleElements: return Diagnostics.Declaration_or_statement_expected;
case ParsingContext.BlockStatements: return Diagnostics.Statement_expected;
case ParsingContext.SwitchClauses: return Diagnostics.case_or_default_expected;
case ParsingContext.SwitchClauseStatements: return Diagnostics.Statement_expected;
case ParsingContext.TypeMembers: return Diagnostics.Property_or_signature_expected;
case ParsingContext.ClassMembers: return Diagnostics.Unexpected_token_A_constructor_method_accessor_or_property_was_expected;
case ParsingContext.EnumMembers: return Diagnostics.Enum_member_expected;
case ParsingContext.BaseTypeReferences: return Diagnostics.Type_reference_expected;
case ParsingContext.VariableDeclarations: return Diagnostics.Variable_declaration_expected;
case ParsingContext.ArgumentExpressions: return Diagnostics.Argument_expression_expected;
case ParsingContext.ObjectLiteralMembers: return Diagnostics.Property_assignment_expected;
case ParsingContext.ArrayLiteralMembers: return Diagnostics.Expression_or_comma_expected;
case ParsingContext.Parameters: return Diagnostics.Parameter_declaration_expected;
case ParsingContext.TypeParameters: return Diagnostics.Type_parameter_declaration_expected;
case ParsingContext.TypeArguments: return Diagnostics.Type_argument_expected;
}
};
enum LookAheadMode {
NotLookingAhead,
NoErrorYet,
Error
}
enum ModifierContext {
SourceElements, // Top level elements in a source file
ModuleElements, // Elements in module declaration
ClassMembers, // Members in class declaration
Parameters, // Parameters in parameter list
}
enum TrailingCommaBehavior {
Disallow,
Allow,
Preserve
}
export function createSourceFile(filename: string, sourceText: string, languageVersion: ScriptTarget): SourceFile {
var file: SourceFile;
var scanner: Scanner;
var token: SyntaxKind;
var parsingContext: ParsingContext;
var commentRanges: TextRange[];
var identifiers: Map<string> = {};
var identifierCount = 0;
var nodeCount = 0;
var lineStarts: number[];
var lookAheadMode = LookAheadMode.NotLookingAhead;
var inAmbientContext = false;
function getLineAndCharacterlFromSourcePosition(position: number) {
if (!lineStarts) {
lineStarts = getLineStarts(sourceText);
}
return getLineAndCharacterOfPosition(lineStarts, position);
}
function error(message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): void {
var start = scanner.getTokenPos();
var length = scanner.getTextPos() - start;
errorAtPos(start, length, message, arg0, arg1, arg2);
}
// This is just like createDiagnosticForNode except that it uses the current file
// being parsed instead of the file containing the node. This is because during
// parse, the nodes do not have parent pointers to get to the file.
//
// It is very intentional that we are not checking or changing the lookAheadMode value
// here. 'grammarErrorOnNode' is called when we are doing extra grammar checks and not
// when we are doing the actual parsing to determine what the user wrote. In other
// words, this function is called once we have already parsed the node, and are just
// applying some stricter checks on that node.
function grammarErrorOnNode(node: Node, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): void {
var start = skipTrivia(file.text, node.pos);
var length = node.end - start;
file.syntacticErrors.push(createFileDiagnostic(file, start, length, message, arg0, arg1, arg2));
}
function grammarErrorAtPos(start: number, length: number, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): void {
file.syntacticErrors.push(createFileDiagnostic(file, start, length, message, arg0, arg1, arg2));
}
function errorAtPos(start: number, length: number, message: DiagnosticMessage, arg0?: any, arg1?: any, arg2?: any): void {
var lastErrorPos = file.syntacticErrors.length
? file.syntacticErrors[file.syntacticErrors.length - 1].start
: -1;
if (start !== lastErrorPos) {
file.syntacticErrors.push(createFileDiagnostic(file, start, length, message, arg0, arg1, arg2));
}
if (lookAheadMode === LookAheadMode.NoErrorYet) {
lookAheadMode = LookAheadMode.Error;
}
}
function scanError(message: DiagnosticMessage) {
var pos = scanner.getTextPos();
errorAtPos(pos, 0, message);
}
function onComment(pos: number, end: number) {
if (commentRanges) commentRanges.push({ pos: pos, end: end });
}
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 lookAheadHelper<T>(callback: () => T, alwaysResetState: 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).
var saveToken = token;
var saveSyntacticErrorsLength = file.syntacticErrors.length;
// Keep track of the current look ahead mode (this matters if we have nested
// speculative parsing).
var saveLookAheadMode = lookAheadMode;
// Mark that we're in speculative parsing and then try to parse out whatever code
// the callback wants.
lookAheadMode = LookAheadMode.NoErrorYet;
var result = callback();
// If we switched from 1 to to -1 then a parse error occurred during the callback.
// If that's the case, then we want to act as if we never got any result at all.
Debug.assert(lookAheadMode === LookAheadMode.Error || lookAheadMode === LookAheadMode.NoErrorYet);
if (lookAheadMode === LookAheadMode.Error) {
result = undefined;
}
// Now restore as appropriate.
lookAheadMode = saveLookAheadMode;
if (!result || alwaysResetState) {
token = saveToken;
file.syntacticErrors.length = saveSyntacticErrorsLength;
}
return result;
}
function lookAhead<T>(callback: () => T): T {
var result: T;
scanner.tryScan(() => {
result = lookAheadHelper(callback, /*alwaysResetState:*/ true);
// Returning false here indicates to the scanner that it should always jump
// back to where it started. This makes sense as 'lookahead' acts as if
// neither the parser nor scanner was affected by the operation.
//
// Note: the rewinding of the parser state is already handled in lookAheadHelper
// (because we passed 'true' for alwaysResetState).
return false;
});
return result;
}
function tryParse<T>(callback: () => T): T {
return scanner.tryScan(() => lookAheadHelper(callback, /*alwaysResetState:*/ false));
}
function isIdentifier(): boolean {
return token === SyntaxKind.Identifier || token > SyntaxKind.LastReservedWord;
}
function isSemicolon(): boolean {
// True if real or automatic semicolon
return token === SyntaxKind.SemicolonToken || token === SyntaxKind.CloseBraceToken || scanner.hasPrecedingLineBreak();
}
function parseExpected(t: SyntaxKind): boolean {
if (token === t) {
nextToken();
return true;
}
error(Diagnostics._0_expected, tokenToString(t));
return false;
}
function parseOptional(t: SyntaxKind): boolean {
if (token === t) {
nextToken();
return true;
}
return false;
}
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(): void {
if (canParseSemicolon()) {
if (token === SyntaxKind.SemicolonToken) {
// consume the semicolon if it was explicitly provided.
nextToken();
}
}
else {
error(Diagnostics._0_expected, ";");
}
}
function createNode(kind: SyntaxKind, pos?: number): Node {
nodeCount++;
var 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();
return node;
}
function createMissingNode(): Node {
return createNode(SyntaxKind.Missing);
}
// 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): Identifier {
identifierCount++;
if (isIdentifier) {
var node = <Identifier>createNode(SyntaxKind.Identifier);
var text = escapeIdentifier(scanner.getTokenValue());
node.text = hasProperty(identifiers, text) ? identifiers[text] : (identifiers[text] = text);
nextToken();
return finishNode(node);
}
error(Diagnostics.Identifier_expected);
return <Identifier>createMissingNode();
}
function parseIdentifier(): Identifier {
return createIdentifier(isIdentifier());
}
function parseIdentifierName(): Identifier {
return createIdentifier(token >= SyntaxKind.Identifier);
}
function isPropertyName(): boolean {
return token >= SyntaxKind.Identifier || token === SyntaxKind.StringLiteral || token === SyntaxKind.NumericLiteral;
}
function parsePropertyName(): Identifier {
if (token === SyntaxKind.StringLiteral || token === SyntaxKind.NumericLiteral) {
return <LiteralExpression>parsePrimaryExpression();
}
return parseIdentifierName();
}
function isKeyword(token: SyntaxKind): boolean {
return SyntaxKind.FirstKeyword <= token && token <= SyntaxKind.LastKeyword;
}
function isModifier(token: SyntaxKind): boolean {
switch (token) {
case SyntaxKind.PublicKeyword:
case SyntaxKind.PrivateKeyword:
case SyntaxKind.StaticKeyword:
case SyntaxKind.ExportKeyword:
case SyntaxKind.DeclareKeyword:
return true;
}
return false;
}
function parseContextualModifier(t: SyntaxKind): boolean {
return token === t && tryParse(() => {
nextToken();
return token === SyntaxKind.OpenBracketToken || isPropertyName();
});
}
function parseAnyContextualModifier(): boolean {
return isModifier(token) && tryParse(() => {
nextToken();
return token === SyntaxKind.OpenBracketToken || isPropertyName();
});
}
// True if positioned at the start of a list element
function isListElement(kind: ParsingContext, inErrorRecovery: boolean): boolean {
switch (kind) {
case ParsingContext.SourceElements:
case ParsingContext.ModuleElements:
return isSourceElement(inErrorRecovery);
case ParsingContext.BlockStatements:
case ParsingContext.SwitchClauseStatements:
return isStatement(inErrorRecovery);
case ParsingContext.SwitchClauses:
return token === SyntaxKind.CaseKeyword || token === SyntaxKind.DefaultKeyword;
case ParsingContext.TypeMembers:
return isTypeMember();
case ParsingContext.ClassMembers:
return lookAhead(isClassMemberStart);
case ParsingContext.EnumMembers:
case ParsingContext.ObjectLiteralMembers:
return isPropertyName();
case ParsingContext.BaseTypeReferences:
return isIdentifier() && ((token !== SyntaxKind.ExtendsKeyword && token !== SyntaxKind.ImplementsKeyword) || !lookAhead(() => (nextToken(), isIdentifier())));
case ParsingContext.VariableDeclarations:
case ParsingContext.TypeParameters:
return isIdentifier();
case ParsingContext.ArgumentExpressions:
return isExpression();
case ParsingContext.ArrayLiteralMembers:
return token === SyntaxKind.CommaToken || isExpression();
case ParsingContext.Parameters:
return isParameter();
case ParsingContext.TypeArguments:
return isType();
}
Debug.fail("Non-exhaustive case in 'isListElement'.");
}
// True if positioned at a list terminator
function isListTerminator(kind: ParsingContext): boolean {
if (token === SyntaxKind.EndOfFileToken) {
// Being at the end of the file ends all lists.
return true;
}
switch (kind) {
case ParsingContext.ModuleElements:
case ParsingContext.BlockStatements:
case ParsingContext.SwitchClauses:
case ParsingContext.TypeMembers:
case ParsingContext.ClassMembers:
case ParsingContext.EnumMembers:
case ParsingContext.ObjectLiteralMembers:
return token === SyntaxKind.CloseBraceToken;
case ParsingContext.SwitchClauseStatements:
return token === SyntaxKind.CloseBraceToken || token === SyntaxKind.CaseKeyword || token === SyntaxKind.DefaultKeyword;
case ParsingContext.BaseTypeReferences:
return token === SyntaxKind.OpenBraceToken || token === SyntaxKind.ExtendsKeyword || token === SyntaxKind.ImplementsKeyword;
case ParsingContext.VariableDeclarations:
return isVariableDeclaratorListTerminator();
case ParsingContext.TypeParameters:
// Tokens other than '>' are here for better error recovery
return token === SyntaxKind.GreaterThanToken || token === SyntaxKind.OpenParenToken || token === SyntaxKind.OpenBraceToken || token === SyntaxKind.ExtendsKeyword || token === SyntaxKind.ImplementsKeyword;
case ParsingContext.ArgumentExpressions:
// Tokens other than ')' are here for better error recovery
return token === SyntaxKind.CloseParenToken || token === SyntaxKind.SemicolonToken;
case ParsingContext.ArrayLiteralMembers:
return token === SyntaxKind.CloseBracketToken;
case ParsingContext.Parameters:
// Tokens other than ')' and ']' (the latter for index signatures) are here for better error recovery
return token === SyntaxKind.CloseParenToken || token === SyntaxKind.CloseBracketToken || token === SyntaxKind.OpenBraceToken;
case ParsingContext.TypeArguments:
// Tokens other than '>' are here for better error recovery
return token === SyntaxKind.GreaterThanToken || token === SyntaxKind.OpenParenToken;
}
}
function isVariableDeclaratorListTerminator(): boolean {
// If we can consume a semicolon (either explicitly, or with ASI), then consider us done
// with parsing the list of variable declarators.
if (canParseSemicolon()) {
return true;
}
// in the case where we're parsing the variable declarator of a 'for-in' statement, we
// are done if we see an 'in' keyword in front of us.
if (token === SyntaxKind.InKeyword) {
return true;
}
// ERROR RECOVERY TWEAK:
// For better error recovery, if we see an '=>' then we just stop immediately. We've got an
// arrow function here and it's going to be very unlikely that we'll resynchronize and get
// another variable declaration.
if (token === SyntaxKind.EqualsGreaterThanToken) {
return true;
}
// Keep trying to parse out variable declarators.
return false;
}
// True if positioned at element or terminator of the current list or any enclosing list
function isInSomeParsingContext(): boolean {
for (var kind = 0; kind < ParsingContext.Count; kind++) {
if (parsingContext & (1 << kind)) {
if (isListElement(kind, /* inErrorRecovery */ true) || isListTerminator(kind)) {
return true;
}
}
}
return false;
}
// Parses a list of elements
function parseList<T extends Node>(kind: ParsingContext, parseElement: () => T): NodeArray<T> {
var saveParsingContext = parsingContext;
parsingContext |= 1 << kind;
var result = <NodeArray<T>>[];
result.pos = getNodePos();
while (!isListTerminator(kind)) {
if (isListElement(kind, /* inErrorRecovery */ false)) {
result.push(parseElement());
}
else {
error(parsingContextErrors(kind));
if (isInSomeParsingContext()) {
break;
}
nextToken();
}
}
result.end = getNodeEnd();
parsingContext = saveParsingContext;
return result;
}
// Parses a comma delimited list of elements
function parseDelimitedList<T extends Node>(kind: ParsingContext, parseElement: () => T, trailingCommaBehavior: TrailingCommaBehavior): NodeArray<T> {
var saveParsingContext = parsingContext;
parsingContext |= 1 << kind;
var result = <NodeArray<T>>[];
result.pos = getNodePos();
// Keep track of how many errors we had before the list started. If we don't see any new
// errors resulting from the list being malformed, we are free to complain about a trailing comma.
var errorCountBeforeParsingList = file.syntacticErrors.length;
var commaStart = -1; // Meaning the previous token was not a comma
while (true) {
if (isListElement(kind, /* inErrorRecovery */ false)) {
result.push(parseElement());
commaStart = scanner.getTokenPos();
if (parseOptional(SyntaxKind.CommaToken)) {
continue;
}
commaStart = -1; // Back to the state where the last token was not a comma
if (isListTerminator(kind)) {
break;
}
error(Diagnostics._0_expected, ",");
}
else if (isListTerminator(kind)) {
// Check if the last token was a comma.
if (commaStart >= 0) {
if (trailingCommaBehavior === TrailingCommaBehavior.Disallow) {
if (file.syntacticErrors.length === errorCountBeforeParsingList) {
// Report a grammar error so we don't affect lookahead
grammarErrorAtPos(commaStart, scanner.getStartPos() - commaStart, Diagnostics.Trailing_comma_not_allowed);
}
}
else if (trailingCommaBehavior === TrailingCommaBehavior.Preserve) {
result.push(<T>createNode(SyntaxKind.OmittedExpression));
}
}
break;
}
else {
error(parsingContextErrors(kind));
if (isInSomeParsingContext()) {
break;
}
nextToken();
}
}
result.end = getNodeEnd();
parsingContext = saveParsingContext;
return result;
}
function createMissingList<T>(): NodeArray<T> {
var pos = getNodePos();
var result = <NodeArray<T>>[];
result.pos = pos;
result.end = pos;
return result;
}
function createNodeArray<T extends Node>(node: T): NodeArray<T> {
var result = <NodeArray<T>>[node];
result.pos = node.pos;
result.end = node.end;
return result;
}
function parseBracketedList<T extends Node>(kind: ParsingContext, parseElement: () => T, startToken: SyntaxKind, endToken: SyntaxKind): NodeArray<T> {
if (parseExpected(startToken)) {
var result = parseDelimitedList(kind, parseElement, TrailingCommaBehavior.Disallow);
parseExpected(endToken);
return result;
}
return createMissingList<T>();
}
function parseEntityName(): EntityName {
var entity: EntityName = parseIdentifier();
while (parseOptional(SyntaxKind.DotToken)) {
var node = <QualifiedName>createNode(SyntaxKind.QualifiedName, entity.pos);
node.left = entity;
node.right = parseIdentifier();
entity = finishNode(node);
}
return entity;
}
function parseTokenNode(): Node {
var node = createNode(token);
nextToken();
return finishNode(node);
}
function parseLiteralNode(): LiteralExpression {
var node = <LiteralExpression>createNode(token);
node.text = scanner.getTokenValue();
nextToken();
return finishNode(node);
}
function parseStringLiteral(): LiteralExpression {
if (token === SyntaxKind.StringLiteral) return parseLiteralNode();
error(Diagnostics.String_literal_expected);
return <LiteralExpression>createMissingNode();
}
// TYPES
function parseTypeReference(): TypeReferenceNode {
var node = <TypeReferenceNode>createNode(SyntaxKind.TypeReference);
node.typeName = parseEntityName();
if (!scanner.hasPrecedingLineBreak() && token === SyntaxKind.LessThanToken) {
node.typeArguments = parseTypeArguments();
}
return finishNode(node);
}
function parseTypeQuery(): TypeQueryNode {
var node = <TypeQueryNode>createNode(SyntaxKind.TypeQuery);
parseExpected(SyntaxKind.TypeOfKeyword);
node.exprName = parseEntityName();
return finishNode(node);
}
function parseTypeParameter(): TypeParameterDeclaration {
var node = <TypeParameterDeclaration>createNode(SyntaxKind.TypeParameter);
node.name = parseIdentifier();
if (parseOptional(SyntaxKind.ExtendsKeyword)) {
// It's not uncommon for people to write improper constraints to a generic. If the
// user writes a constraint that is an expression and not an actual type, then parse
// it out as an expression (so we can recover well), but report that a type is needed
// instead.
if (isType() || !isExpression()) {
node.constraint = parseType();
}
else {
// It was not a type, and it looked like an expression. Parse out an expression
// here so we recover well. Note: it is important that we call parseUnaryExpression
// and not parseExpression here. If the user has:
//
// <T extends "">
//
// We do *not* want to consume the > as we're consuming the expression for "".
var expr = parseUnaryExpression();
grammarErrorOnNode(expr, Diagnostics.Type_expected);
}
}
return finishNode(node);
}
function parseTypeParameters(): NodeArray<TypeParameterDeclaration> {
if (token === SyntaxKind.LessThanToken) {
var pos = getNodePos();
var result = parseBracketedList(ParsingContext.TypeParameters, parseTypeParameter, SyntaxKind.LessThanToken, SyntaxKind.GreaterThanToken);
if (!result.length) {
var start = getTokenPos(pos);
var length = getNodePos() - start;
errorAtPos(start, length, Diagnostics.Type_parameter_list_cannot_be_empty);
}
return result;
}
}
function parseParameterType(): TypeNode {
return parseOptional(SyntaxKind.ColonToken) ? token === SyntaxKind.StringLiteral ? parseStringLiteral() : parseType() : undefined;
}
function isParameter(): boolean {
return token === SyntaxKind.DotDotDotToken || isIdentifier() || isModifier(token);
}
function parseParameter(flags: NodeFlags = 0): ParameterDeclaration {
var node = <ParameterDeclaration>createNode(SyntaxKind.Parameter);
node.flags |= parseAndCheckModifiers(ModifierContext.Parameters);
if (parseOptional(SyntaxKind.DotDotDotToken)) {
node.flags |= NodeFlags.Rest;
}
node.name = parseIdentifier();
if (parseOptional(SyntaxKind.QuestionToken)) {
node.flags |= NodeFlags.QuestionMark;
}
node.type = parseParameterType();
node.initializer = parseInitializer(/*inParameter*/ true);
// Do not check for initializers in an ambient context for parameters. This is not
// a grammar error because the grammar allows arbitrary call signatures in
// an ambient context.
// It is actually not necessary for this to be an error at all. The reason is that
// function/constructor implementations are syntactically disallowed in ambient
// contexts. In addition, parameter initializers are semantically disallowed in
// overload signatures. So parameter initializers are transitively disallowed in
// ambient contexts.
return finishNode(node);
}
function parseSignature(kind: SyntaxKind, returnToken: SyntaxKind): ParsedSignature {
if (kind === SyntaxKind.ConstructSignature) {
parseExpected(SyntaxKind.NewKeyword);
}
var typeParameters = parseTypeParameters();
var parameters = parseParameterList(SyntaxKind.OpenParenToken, SyntaxKind.CloseParenToken);
checkParameterList(parameters);
var type = parseOptional(returnToken) ? parseType() : undefined;
return {
typeParameters: typeParameters,
parameters: parameters,
type: type
};
}
// Because we use this for index signatures as well, we sometimes use
// parentheses, and sometimes use brackets.
function parseParameterList(startDelimiter: SyntaxKind, endDelimiter: SyntaxKind) {
return parseBracketedList(ParsingContext.Parameters, parseParameter, startDelimiter, endDelimiter);
}
function checkParameterList(parameters: NodeArray<ParameterDeclaration>): void {
var seenOptionalParameter = false;
var parameterCount = parameters.length;
for (var i = 0; i < parameterCount; i++) {
var parameter = parameters[i];
if (parameter.flags & NodeFlags.Rest) {
if (i !== (parameterCount - 1)) {
grammarErrorOnNode(parameter.name, Diagnostics.A_rest_parameter_must_be_last_in_a_parameter_list);
return;
}
if (parameter.flags & NodeFlags.QuestionMark) {
grammarErrorOnNode(parameter.name, Diagnostics.A_rest_parameter_cannot_be_optional);
return;
}
if (parameter.initializer) {
grammarErrorOnNode(parameter.name, Diagnostics.A_rest_parameter_cannot_have_an_initializer);
return;
}
}
else if (parameter.flags & NodeFlags.QuestionMark || parameter.initializer) {
seenOptionalParameter = true;
if (parameter.flags & NodeFlags.QuestionMark && parameter.initializer) {