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/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import * as chars from '../chars';
import {DEFAULT_INTERPOLATION_CONFIG, InterpolationConfig} from '../ml_parser/interpolation_config';
import {InterpolatedAttributeToken, InterpolatedTextToken, TokenType as MlParserTokenType} from '../ml_parser/tokens';
import {AbsoluteSourceSpan, AST, ASTWithSource, Binary, BindingPipe, Call, Chain, Conditional, EmptyExpr, ExpressionBinding, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralMapKey, LiteralPrimitive, NonNullAssert, ParserError, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, RecursiveAstVisitor, SafeCall, SafeKeyedRead, SafePropertyRead, TemplateBinding, TemplateBindingIdentifier, ThisReceiver, Unary, VariableBinding} from './ast';
import {EOF, Lexer, Token, TokenType} from './lexer';
export interface InterpolationPiece {
text: string;
start: number;
end: number;
}
export class SplitInterpolation {
constructor(
public strings: InterpolationPiece[], public expressions: InterpolationPiece[],
public offsets: number[]) {}
}
export class TemplateBindingParseResult {
constructor(
public templateBindings: TemplateBinding[], public warnings: string[],
public errors: ParserError[]) {}
}
/**
* Represents the possible parse modes to be used as a bitmask.
*/
export const enum ParseFlags {
None = 0,
/**
* Whether an output binding is being parsed.
*/
Action = 1 << 0,
/**
* Whether an assignment event is being parsed, i.e. an expression originating from
* two-way-binding aka banana-in-a-box syntax.
*/
AssignmentEvent = 1 << 1,
}
export class Parser {
private errors: ParserError[] = [];
constructor(private _lexer: Lexer) {}
parseAction(
input: string, isAssignmentEvent: boolean, location: string, absoluteOffset: number,
interpolationConfig: InterpolationConfig = DEFAULT_INTERPOLATION_CONFIG): ASTWithSource {
this._checkNoInterpolation(input, location, interpolationConfig);
const sourceToLex = this._stripComments(input);
const tokens = this._lexer.tokenize(sourceToLex);
let flags = ParseFlags.Action;
if (isAssignmentEvent) {
flags |= ParseFlags.AssignmentEvent;
}
const ast =
new _ParseAST(input, location, absoluteOffset, tokens, flags, this.errors, 0).parseChain();
return new ASTWithSource(ast, input, location, absoluteOffset, this.errors);
}
parseBinding(
input: string, location: string, absoluteOffset: number,
interpolationConfig: InterpolationConfig = DEFAULT_INTERPOLATION_CONFIG): ASTWithSource {
const ast = this._parseBindingAst(input, location, absoluteOffset, interpolationConfig);
return new ASTWithSource(ast, input, location, absoluteOffset, this.errors);
}
private checkSimpleExpression(ast: AST): string[] {
const checker = new SimpleExpressionChecker();
ast.visit(checker);
return checker.errors;
}
// Host bindings parsed here
parseSimpleBinding(
input: string, location: string, absoluteOffset: number,
interpolationConfig: InterpolationConfig = DEFAULT_INTERPOLATION_CONFIG): ASTWithSource {
const ast = this._parseBindingAst(input, location, absoluteOffset, interpolationConfig);
const errors = this.checkSimpleExpression(ast);
if (errors.length > 0) {
this._reportError(
`Host binding expression cannot contain ${errors.join(' ')}`, input, location);
}
return new ASTWithSource(ast, input, location, absoluteOffset, this.errors);
}
private _reportError(message: string, input: string, errLocation: string, ctxLocation?: string) {
this.errors.push(new ParserError(message, input, errLocation, ctxLocation));
}
private _parseBindingAst(
input: string, location: string, absoluteOffset: number,
interpolationConfig: InterpolationConfig): AST {
this._checkNoInterpolation(input, location, interpolationConfig);
const sourceToLex = this._stripComments(input);
const tokens = this._lexer.tokenize(sourceToLex);
return new _ParseAST(input, location, absoluteOffset, tokens, ParseFlags.None, this.errors, 0)
.parseChain();
}
/**
* Parse microsyntax template expression and return a list of bindings or
* parsing errors in case the given expression is invalid.
*
* For example,
* ```
* <div *ngFor="let item of items">
* ^ ^ absoluteValueOffset for `templateValue`
* absoluteKeyOffset for `templateKey`
* ```
* contains three bindings:
* 1. ngFor -> null
* 2. item -> NgForOfContext.$implicit
* 3. ngForOf -> items
*
* This is apparent from the de-sugared template:
* ```
* <ng-template ngFor let-item [ngForOf]="items">
* ```
*
* @param templateKey name of directive, without the * prefix. For example: ngIf, ngFor
* @param templateValue RHS of the microsyntax attribute
* @param templateUrl template filename if it's external, component filename if it's inline
* @param absoluteKeyOffset start of the `templateKey`
* @param absoluteValueOffset start of the `templateValue`
*/
parseTemplateBindings(
templateKey: string, templateValue: string, templateUrl: string, absoluteKeyOffset: number,
absoluteValueOffset: number): TemplateBindingParseResult {
const tokens = this._lexer.tokenize(templateValue);
const parser = new _ParseAST(
templateValue, templateUrl, absoluteValueOffset, tokens, ParseFlags.None, this.errors,
0 /* relative offset */);
return parser.parseTemplateBindings({
source: templateKey,
span: new AbsoluteSourceSpan(absoluteKeyOffset, absoluteKeyOffset + templateKey.length),
});
}
parseInterpolation(
input: string, location: string, absoluteOffset: number,
interpolatedTokens: InterpolatedAttributeToken[]|InterpolatedTextToken[]|null,
interpolationConfig: InterpolationConfig = DEFAULT_INTERPOLATION_CONFIG): ASTWithSource|null {
const {strings, expressions, offsets} =
this.splitInterpolation(input, location, interpolatedTokens, interpolationConfig);
if (expressions.length === 0) return null;
const expressionNodes: AST[] = [];
for (let i = 0; i < expressions.length; ++i) {
const expressionText = expressions[i].text;
const sourceToLex = this._stripComments(expressionText);
const tokens = this._lexer.tokenize(sourceToLex);
const ast =
new _ParseAST(
input, location, absoluteOffset, tokens, ParseFlags.None, this.errors, offsets[i])
.parseChain();
expressionNodes.push(ast);
}
return this.createInterpolationAst(
strings.map(s => s.text), expressionNodes, input, location, absoluteOffset);
}
/**
* Similar to `parseInterpolation`, but treats the provided string as a single expression
* element that would normally appear within the interpolation prefix and suffix (`{{` and `}}`).
* This is used for parsing the switch expression in ICUs.
*/
parseInterpolationExpression(expression: string, location: string, absoluteOffset: number):
ASTWithSource {
const sourceToLex = this._stripComments(expression);
const tokens = this._lexer.tokenize(sourceToLex);
const ast =
new _ParseAST(expression, location, absoluteOffset, tokens, ParseFlags.None, this.errors, 0)
.parseChain();
const strings = ['', '']; // The prefix and suffix strings are both empty
return this.createInterpolationAst(strings, [ast], expression, location, absoluteOffset);
}
private createInterpolationAst(
strings: string[], expressions: AST[], input: string, location: string,
absoluteOffset: number): ASTWithSource {
const span = new ParseSpan(0, input.length);
const interpolation =
new Interpolation(span, span.toAbsolute(absoluteOffset), strings, expressions);
return new ASTWithSource(interpolation, input, location, absoluteOffset, this.errors);
}
/**
* Splits a string of text into "raw" text segments and expressions present in interpolations in
* the string.
* Returns `null` if there are no interpolations, otherwise a
* `SplitInterpolation` with splits that look like
* <raw text> <expression> <raw text> ... <raw text> <expression> <raw text>
*/
splitInterpolation(
input: string, location: string,
interpolatedTokens: InterpolatedAttributeToken[]|InterpolatedTextToken[]|null,
interpolationConfig: InterpolationConfig = DEFAULT_INTERPOLATION_CONFIG): SplitInterpolation {
const strings: InterpolationPiece[] = [];
const expressions: InterpolationPiece[] = [];
const offsets: number[] = [];
const inputToTemplateIndexMap =
interpolatedTokens ? getIndexMapForOriginalTemplate(interpolatedTokens) : null;
let i = 0;
let atInterpolation = false;
let extendLastString = false;
let {start: interpStart, end: interpEnd} = interpolationConfig;
while (i < input.length) {
if (!atInterpolation) {
// parse until starting {{
const start = i;
i = input.indexOf(interpStart, i);
if (i === -1) {
i = input.length;
}
const text = input.substring(start, i);
strings.push({text, start, end: i});
atInterpolation = true;
} else {
// parse from starting {{ to ending }} while ignoring content inside quotes.
const fullStart = i;
const exprStart = fullStart + interpStart.length;
const exprEnd = this._getInterpolationEndIndex(input, interpEnd, exprStart);
if (exprEnd === -1) {
// Could not find the end of the interpolation; do not parse an expression.
// Instead we should extend the content on the last raw string.
atInterpolation = false;
extendLastString = true;
break;
}
const fullEnd = exprEnd + interpEnd.length;
const text = input.substring(exprStart, exprEnd);
if (text.trim().length === 0) {
this._reportError(
'Blank expressions are not allowed in interpolated strings', input,
`at column ${i} in`, location);
}
expressions.push({text, start: fullStart, end: fullEnd});
const startInOriginalTemplate = inputToTemplateIndexMap?.get(fullStart) ?? fullStart;
const offset = startInOriginalTemplate + interpStart.length;
offsets.push(offset);
i = fullEnd;
atInterpolation = false;
}
}
if (!atInterpolation) {
// If we are now at a text section, add the remaining content as a raw string.
if (extendLastString) {
const piece = strings[strings.length - 1];
piece.text += input.substring(i);
piece.end = input.length;
} else {
strings.push({text: input.substring(i), start: i, end: input.length});
}
}
return new SplitInterpolation(strings, expressions, offsets);
}
wrapLiteralPrimitive(input: string|null, location: string, absoluteOffset: number):
ASTWithSource {
const span = new ParseSpan(0, input == null ? 0 : input.length);
return new ASTWithSource(
new LiteralPrimitive(span, span.toAbsolute(absoluteOffset), input), input, location,
absoluteOffset, this.errors);
}
private _stripComments(input: string): string {
const i = this._commentStart(input);
return i != null ? input.substring(0, i) : input;
}
private _commentStart(input: string): number|null {
let outerQuote: number|null = null;
for (let i = 0; i < input.length - 1; i++) {
const char = input.charCodeAt(i);
const nextChar = input.charCodeAt(i + 1);
if (char === chars.$SLASH && nextChar == chars.$SLASH && outerQuote == null) return i;
if (outerQuote === char) {
outerQuote = null;
} else if (outerQuote == null && chars.isQuote(char)) {
outerQuote = char;
}
}
return null;
}
private _checkNoInterpolation(input: string, location: string, {start, end}: InterpolationConfig):
void {
let startIndex = -1;
let endIndex = -1;
for (const charIndex of this._forEachUnquotedChar(input, 0)) {
if (startIndex === -1) {
if (input.startsWith(start)) {
startIndex = charIndex;
}
} else {
endIndex = this._getInterpolationEndIndex(input, end, charIndex);
if (endIndex > -1) {
break;
}
}
}
if (startIndex > -1 && endIndex > -1) {
this._reportError(
`Got interpolation (${start}${end}) where expression was expected`, input,
`at column ${startIndex} in`, location);
}
}
/**
* Finds the index of the end of an interpolation expression
* while ignoring comments and quoted content.
*/
private _getInterpolationEndIndex(input: string, expressionEnd: string, start: number): number {
for (const charIndex of this._forEachUnquotedChar(input, start)) {
if (input.startsWith(expressionEnd, charIndex)) {
return charIndex;
}
// Nothing else in the expression matters after we've
// hit a comment so look directly for the end token.
if (input.startsWith('//', charIndex)) {
return input.indexOf(expressionEnd, charIndex);
}
}
return -1;
}
/**
* Generator used to iterate over the character indexes of a string that are outside of quotes.
* @param input String to loop through.
* @param start Index within the string at which to start.
*/
private * _forEachUnquotedChar(input: string, start: number) {
let currentQuote: string|null = null;
let escapeCount = 0;
for (let i = start; i < input.length; i++) {
const char = input[i];
// Skip the characters inside quotes. Note that we only care about the outer-most
// quotes matching up and we need to account for escape characters.
if (chars.isQuote(input.charCodeAt(i)) && (currentQuote === null || currentQuote === char) &&
escapeCount % 2 === 0) {
currentQuote = currentQuote === null ? char : null;
} else if (currentQuote === null) {
yield i;
}
escapeCount = char === '\\' ? escapeCount + 1 : 0;
}
}
}
/** Describes a stateful context an expression parser is in. */
enum ParseContextFlags {
None = 0,
/**
* A Writable context is one in which a value may be written to an lvalue.
* For example, after we see a property access, we may expect a write to the
* property via the "=" operator.
* prop
* ^ possible "=" after
*/
Writable = 1,
}
export class _ParseAST {
private rparensExpected = 0;
private rbracketsExpected = 0;
private rbracesExpected = 0;
private context = ParseContextFlags.None;
// Cache of expression start and input indeces to the absolute source span they map to, used to
// prevent creating superfluous source spans in `sourceSpan`.
// A serial of the expression start and input index is used for mapping because both are stateful
// and may change for subsequent expressions visited by the parser.
private sourceSpanCache = new Map<string, AbsoluteSourceSpan>();
index: number = 0;
constructor(
public input: string, public location: string, public absoluteOffset: number,
public tokens: Token[], public parseFlags: ParseFlags, private errors: ParserError[],
private offset: number) {}
peek(offset: number): Token {
const i = this.index + offset;
return i < this.tokens.length ? this.tokens[i] : EOF;
}
get next(): Token {
return this.peek(0);
}
/** Whether all the parser input has been processed. */
get atEOF(): boolean {
return this.index >= this.tokens.length;
}
/**
* Index of the next token to be processed, or the end of the last token if all have been
* processed.
*/
get inputIndex(): number {
return this.atEOF ? this.currentEndIndex : this.next.index + this.offset;
}
/**
* End index of the last processed token, or the start of the first token if none have been
* processed.
*/
get currentEndIndex(): number {
if (this.index > 0) {
const curToken = this.peek(-1);
return curToken.end + this.offset;
}
// No tokens have been processed yet; return the next token's start or the length of the input
// if there is no token.
if (this.tokens.length === 0) {
return this.input.length + this.offset;
}
return this.next.index + this.offset;
}
/**
* Returns the absolute offset of the start of the current token.
*/
get currentAbsoluteOffset(): number {
return this.absoluteOffset + this.inputIndex;
}
/**
* Retrieve a `ParseSpan` from `start` to the current position (or to `artificialEndIndex` if
* provided).
*
* @param start Position from which the `ParseSpan` will start.
* @param artificialEndIndex Optional ending index to be used if provided (and if greater than the
* natural ending index)
*/
span(start: number, artificialEndIndex?: number): ParseSpan {
let endIndex = this.currentEndIndex;
if (artificialEndIndex !== undefined && artificialEndIndex > this.currentEndIndex) {
endIndex = artificialEndIndex;
}
// In some unusual parsing scenarios (like when certain tokens are missing and an `EmptyExpr` is
// being created), the current token may already be advanced beyond the `currentEndIndex`. This
// appears to be a deep-seated parser bug.
//
// As a workaround for now, swap the start and end indices to ensure a valid `ParseSpan`.
// TODO(alxhub): fix the bug upstream in the parser state, and remove this workaround.
if (start > endIndex) {
const tmp = endIndex;
endIndex = start;
start = tmp;
}
return new ParseSpan(start, endIndex);
}
sourceSpan(start: number, artificialEndIndex?: number): AbsoluteSourceSpan {
const serial = `${start}@${this.inputIndex}:${artificialEndIndex}`;
if (!this.sourceSpanCache.has(serial)) {
this.sourceSpanCache.set(
serial, this.span(start, artificialEndIndex).toAbsolute(this.absoluteOffset));
}
return this.sourceSpanCache.get(serial)!;
}
advance() {
this.index++;
}
/**
* Executes a callback in the provided context.
*/
private withContext<T>(context: ParseContextFlags, cb: () => T): T {
this.context |= context;
const ret = cb();
this.context ^= context;
return ret;
}
consumeOptionalCharacter(code: number): boolean {
if (this.next.isCharacter(code)) {
this.advance();
return true;
} else {
return false;
}
}
peekKeywordLet(): boolean {
return this.next.isKeywordLet();
}
peekKeywordAs(): boolean {
return this.next.isKeywordAs();
}
/**
* Consumes an expected character, otherwise emits an error about the missing expected character
* and skips over the token stream until reaching a recoverable point.
*
* See `this.error` and `this.skip` for more details.
*/
expectCharacter(code: number) {
if (this.consumeOptionalCharacter(code)) return;
this.error(`Missing expected ${String.fromCharCode(code)}`);
}
consumeOptionalOperator(op: string): boolean {
if (this.next.isOperator(op)) {
this.advance();
return true;
} else {
return false;
}
}
expectOperator(operator: string) {
if (this.consumeOptionalOperator(operator)) return;
this.error(`Missing expected operator ${operator}`);
}
prettyPrintToken(tok: Token): string {
return tok === EOF ? 'end of input' : `token ${tok}`;
}
expectIdentifierOrKeyword(): string|null {
const n = this.next;
if (!n.isIdentifier() && !n.isKeyword()) {
if (n.isPrivateIdentifier()) {
this._reportErrorForPrivateIdentifier(n, 'expected identifier or keyword');
} else {
this.error(`Unexpected ${this.prettyPrintToken(n)}, expected identifier or keyword`);
}
return null;
}
this.advance();
return n.toString() as string;
}
expectIdentifierOrKeywordOrString(): string {
const n = this.next;
if (!n.isIdentifier() && !n.isKeyword() && !n.isString()) {
if (n.isPrivateIdentifier()) {
this._reportErrorForPrivateIdentifier(n, 'expected identifier, keyword or string');
} else {
this.error(
`Unexpected ${this.prettyPrintToken(n)}, expected identifier, keyword, or string`);
}
return '';
}
this.advance();
return n.toString() as string;
}
parseChain(): AST {
const exprs: AST[] = [];
const start = this.inputIndex;
while (this.index < this.tokens.length) {
const expr = this.parsePipe();
exprs.push(expr);
if (this.consumeOptionalCharacter(chars.$SEMICOLON)) {
if (!(this.parseFlags & ParseFlags.Action)) {
this.error('Binding expression cannot contain chained expression');
}
while (this.consumeOptionalCharacter(chars.$SEMICOLON)) {
} // read all semicolons
} else if (this.index < this.tokens.length) {
const errorIndex = this.index;
this.error(`Unexpected token '${this.next}'`);
// The `error` call above will skip ahead to the next recovery point in an attempt to
// recover part of the expression, but that might be the token we started from which will
// lead to an infinite loop. If that's the case, break the loop assuming that we can't
// parse further.
if (this.index === errorIndex) {
break;
}
}
}
if (exprs.length === 0) {
// We have no expressions so create an empty expression that spans the entire input length
const artificialStart = this.offset;
const artificialEnd = this.offset + this.input.length;
return new EmptyExpr(
this.span(artificialStart, artificialEnd),
this.sourceSpan(artificialStart, artificialEnd));
}
if (exprs.length == 1) return exprs[0];
return new Chain(this.span(start), this.sourceSpan(start), exprs);
}
parsePipe(): AST {
const start = this.inputIndex;
let result = this.parseExpression();
if (this.consumeOptionalOperator('|')) {
if (this.parseFlags & ParseFlags.Action) {
this.error('Cannot have a pipe in an action expression');
}
do {
const nameStart = this.inputIndex;
let nameId = this.expectIdentifierOrKeyword();
let nameSpan: AbsoluteSourceSpan;
let fullSpanEnd: number|undefined = undefined;
if (nameId !== null) {
nameSpan = this.sourceSpan(nameStart);
} else {
// No valid identifier was found, so we'll assume an empty pipe name ('').
nameId = '';
// However, there may have been whitespace present between the pipe character and the next
// token in the sequence (or the end of input). We want to track this whitespace so that
// the `BindingPipe` we produce covers not just the pipe character, but any trailing
// whitespace beyond it. Another way of thinking about this is that the zero-length name
// is assumed to be at the end of any whitespace beyond the pipe character.
//
// Therefore, we push the end of the `ParseSpan` for this pipe all the way up to the
// beginning of the next token, or until the end of input if the next token is EOF.
fullSpanEnd = this.next.index !== -1 ? this.next.index : this.input.length + this.offset;
// The `nameSpan` for an empty pipe name is zero-length at the end of any whitespace
// beyond the pipe character.
nameSpan = new ParseSpan(fullSpanEnd, fullSpanEnd).toAbsolute(this.absoluteOffset);
}
const args: AST[] = [];
while (this.consumeOptionalCharacter(chars.$COLON)) {
args.push(this.parseExpression());
// If there are additional expressions beyond the name, then the artificial end for the
// name is no longer relevant.
}
result = new BindingPipe(
this.span(start), this.sourceSpan(start, fullSpanEnd), result, nameId, args, nameSpan);
} while (this.consumeOptionalOperator('|'));
}
return result;
}
parseExpression(): AST {
return this.parseConditional();
}
parseConditional(): AST {
const start = this.inputIndex;
const result = this.parseLogicalOr();
if (this.consumeOptionalOperator('?')) {
const yes = this.parsePipe();
let no: AST;
if (!this.consumeOptionalCharacter(chars.$COLON)) {
const end = this.inputIndex;
const expression = this.input.substring(start, end);
this.error(`Conditional expression ${expression} requires all 3 expressions`);
no = new EmptyExpr(this.span(start), this.sourceSpan(start));
} else {
no = this.parsePipe();
}
return new Conditional(this.span(start), this.sourceSpan(start), result, yes, no);
} else {
return result;
}
}
parseLogicalOr(): AST {
// '||'
const start = this.inputIndex;
let result = this.parseLogicalAnd();
while (this.consumeOptionalOperator('||')) {
const right = this.parseLogicalAnd();
result = new Binary(this.span(start), this.sourceSpan(start), '||', result, right);
}
return result;
}
parseLogicalAnd(): AST {
// '&&'
const start = this.inputIndex;
let result = this.parseNullishCoalescing();
while (this.consumeOptionalOperator('&&')) {
const right = this.parseNullishCoalescing();
result = new Binary(this.span(start), this.sourceSpan(start), '&&', result, right);
}
return result;
}
parseNullishCoalescing(): AST {
// '??'
const start = this.inputIndex;
let result = this.parseEquality();
while (this.consumeOptionalOperator('??')) {
const right = this.parseEquality();
result = new Binary(this.span(start), this.sourceSpan(start), '??', result, right);
}
return result;
}
parseEquality(): AST {
// '==','!=','===','!=='
const start = this.inputIndex;
let result = this.parseRelational();
while (this.next.type == TokenType.Operator) {
const operator = this.next.strValue;
switch (operator) {
case '==':
case '===':
case '!=':
case '!==':
this.advance();
const right = this.parseRelational();
result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right);
continue;
}
break;
}
return result;
}
parseRelational(): AST {
// '<', '>', '<=', '>='
const start = this.inputIndex;
let result = this.parseAdditive();
while (this.next.type == TokenType.Operator) {
const operator = this.next.strValue;
switch (operator) {
case '<':
case '>':
case '<=':
case '>=':
this.advance();
const right = this.parseAdditive();
result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right);
continue;
}
break;
}
return result;
}
parseAdditive(): AST {
// '+', '-'
const start = this.inputIndex;
let result = this.parseMultiplicative();
while (this.next.type == TokenType.Operator) {
const operator = this.next.strValue;
switch (operator) {
case '+':
case '-':
this.advance();
let right = this.parseMultiplicative();
result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right);
continue;
}
break;
}
return result;
}
parseMultiplicative(): AST {
// '*', '%', '/'
const start = this.inputIndex;
let result = this.parsePrefix();
while (this.next.type == TokenType.Operator) {
const operator = this.next.strValue;
switch (operator) {
case '*':
case '%':
case '/':
this.advance();
let right = this.parsePrefix();
result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right);
continue;
}
break;
}
return result;
}
parsePrefix(): AST {
if (this.next.type == TokenType.Operator) {
const start = this.inputIndex;
const operator = this.next.strValue;
let result: AST;
switch (operator) {
case '+':
this.advance();
result = this.parsePrefix();
return Unary.createPlus(this.span(start), this.sourceSpan(start), result);
case '-':
this.advance();
result = this.parsePrefix();
return Unary.createMinus(this.span(start), this.sourceSpan(start), result);
case '!':
this.advance();
result = this.parsePrefix();
return new PrefixNot(this.span(start), this.sourceSpan(start), result);
}
}
return this.parseCallChain();
}
parseCallChain(): AST {
const start = this.inputIndex;
let result = this.parsePrimary();
while (true) {
if (this.consumeOptionalCharacter(chars.$PERIOD)) {
result = this.parseAccessMember(result, start, false);
} else if (this.consumeOptionalOperator('?.')) {
if (this.consumeOptionalCharacter(chars.$LPAREN)) {
result = this.parseCall(result, start, true);
} else {
result = this.consumeOptionalCharacter(chars.$LBRACKET) ?
this.parseKeyedReadOrWrite(result, start, true) :
this.parseAccessMember(result, start, true);
}
} else if (this.consumeOptionalCharacter(chars.$LBRACKET)) {
result = this.parseKeyedReadOrWrite(result, start, false);
} else if (this.consumeOptionalCharacter(chars.$LPAREN)) {
result = this.parseCall(result, start, false);
} else if (this.consumeOptionalOperator('!')) {
result = new NonNullAssert(this.span(start), this.sourceSpan(start), result);
} else {
return result;
}
}
}
parsePrimary(): AST {
const start = this.inputIndex;
if (this.consumeOptionalCharacter(chars.$LPAREN)) {
this.rparensExpected++;
const result = this.parsePipe();
this.rparensExpected--;
this.expectCharacter(chars.$RPAREN);
return result;
} else if (this.next.isKeywordNull()) {
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), null);
} else if (this.next.isKeywordUndefined()) {
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), void 0);
} else if (this.next.isKeywordTrue()) {
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), true);
} else if (this.next.isKeywordFalse()) {
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), false);
} else if (this.next.isKeywordThis()) {
this.advance();
return new ThisReceiver(this.span(start), this.sourceSpan(start));
} else if (this.consumeOptionalCharacter(chars.$LBRACKET)) {
this.rbracketsExpected++;
const elements = this.parseExpressionList(chars.$RBRACKET);
this.rbracketsExpected--;
this.expectCharacter(chars.$RBRACKET);
return new LiteralArray(this.span(start), this.sourceSpan(start), elements);
} else if (this.next.isCharacter(chars.$LBRACE)) {
return this.parseLiteralMap();
} else if (this.next.isIdentifier()) {
return this.parseAccessMember(
new ImplicitReceiver(this.span(start), this.sourceSpan(start)), start, false);
} else if (this.next.isNumber()) {
const value = this.next.toNumber();
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), value);
} else if (this.next.isString()) {
const literalValue = this.next.toString();
this.advance();
return new LiteralPrimitive(this.span(start), this.sourceSpan(start), literalValue);
} else if (this.next.isPrivateIdentifier()) {
this._reportErrorForPrivateIdentifier(this.next, null);
return new EmptyExpr(this.span(start), this.sourceSpan(start));
} else if (this.index >= this.tokens.length) {
this.error(`Unexpected end of expression: ${this.input}`);
return new EmptyExpr(this.span(start), this.sourceSpan(start));
} else {
this.error(`Unexpected token ${this.next}`);
return new EmptyExpr(this.span(start), this.sourceSpan(start));
}
}
parseExpressionList(terminator: number): AST[] {
const result: AST[] = [];
do {
if (!this.next.isCharacter(terminator)) {
result.push(this.parsePipe());
} else {
break;
}
} while (this.consumeOptionalCharacter(chars.$COMMA));
return result;
}
parseLiteralMap(): LiteralMap {
const keys: LiteralMapKey[] = [];
const values: AST[] = [];
const start = this.inputIndex;
this.expectCharacter(chars.$LBRACE);
if (!this.consumeOptionalCharacter(chars.$RBRACE)) {
this.rbracesExpected++;
do {
const keyStart = this.inputIndex;
const quoted = this.next.isString();
const key = this.expectIdentifierOrKeywordOrString();
keys.push({key, quoted});
// Properties with quoted keys can't use the shorthand syntax.
if (quoted) {
this.expectCharacter(chars.$COLON);
values.push(this.parsePipe());
} else if (this.consumeOptionalCharacter(chars.$COLON)) {
values.push(this.parsePipe());
} else {
const span = this.span(keyStart);
const sourceSpan = this.sourceSpan(keyStart);
values.push(new PropertyRead(
span, sourceSpan, sourceSpan, new ImplicitReceiver(span, sourceSpan), key));
}
} while (this.consumeOptionalCharacter(chars.$COMMA) &&
!this.next.isCharacter(chars.$RBRACE));
this.rbracesExpected--;
this.expectCharacter(chars.$RBRACE);
}
return new LiteralMap(this.span(start), this.sourceSpan(start), keys, values);
}
parseAccessMember(readReceiver: AST, start: number, isSafe: boolean): AST {
const nameStart = this.inputIndex;
const id = this.withContext(ParseContextFlags.Writable, () => {
const id = this.expectIdentifierOrKeyword() ?? '';
if (id.length === 0) {
this.error(`Expected identifier for property access`, readReceiver.span.end);
}
return id;
});
const nameSpan = this.sourceSpan(nameStart);
let receiver: AST;
if (isSafe) {
if (this.consumeOptionalAssignment()) {
this.error('The \'?.\' operator cannot be used in the assignment');
receiver = new EmptyExpr(this.span(start), this.sourceSpan(start));
} else {
receiver = new SafePropertyRead(
this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id);
}
} else {
if (this.consumeOptionalAssignment()) {
if (!(this.parseFlags & ParseFlags.Action)) {
this.error('Bindings cannot contain assignments');
return new EmptyExpr(this.span(start), this.sourceSpan(start));
}
const value = this.parseConditional();
receiver = new PropertyWrite(
this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id, value);
} else {
receiver =
new PropertyRead(this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id);
}
}
return receiver;
}
parseCall(receiver: AST, start: number, isSafe: boolean): AST {