packages/compiler/src/expression_parser/ast.ts - main - githubmirror/angular

packages/compiler/src/expression_parser/ast.ts
952 строки26 KB
Matthieu Riegler
feat(compiler): Add support for the `instanceof` binary operator
13 янв 2026, 19:33
13 янв 2026, 19:3372534e2
/**
 * @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.dev/license
 */

import {SecurityContext} from '../core';
import {ParseError, ParseSourceSpan} from '../parse_util';

export class ParseSpan {
  constructor(
    public start: number,
    public end: number,
  ) {}
  toAbsolute(absoluteOffset: number): AbsoluteSourceSpan {
    return new AbsoluteSourceSpan(absoluteOffset + this.start, absoluteOffset + this.end);
  }
}

export abstract class AST {
  constructor(
    public span: ParseSpan,
    /**
     * Absolute location of the expression AST in a source code file.
     */
    public sourceSpan: AbsoluteSourceSpan,
  ) {}

  abstract visit(visitor: AstVisitor, context?: any): any;

  toString(): string {
    return 'AST';
  }
}

export abstract class ASTWithName extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public nameSpan: AbsoluteSourceSpan,
  ) {
    super(span, sourceSpan);
  }
}

export class EmptyExpr extends AST {
  override visit(visitor: AstVisitor, context: any = null) {
    return visitor.visitEmptyExpr?.(this, context);
  }
}

export class ImplicitReceiver extends AST {
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitImplicitReceiver(this, context);
  }
}

export class ThisReceiver extends AST {
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitThisReceiver?.(this, context);
  }
}

/**
 * Multiple expressions separated by a semicolon.
 */
export class Chain extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expressions: AST[],
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitChain(this, context);
  }
}

export class Conditional extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public condition: AST,
    public trueExp: AST,
    public falseExp: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitConditional(this, context);
  }
}

export class PropertyRead extends ASTWithName {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    nameSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public name: string,
  ) {
    super(span, sourceSpan, nameSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitPropertyRead(this, context);
  }
}

export class SafePropertyRead extends ASTWithName {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    nameSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public name: string,
  ) {
    super(span, sourceSpan, nameSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitSafePropertyRead(this, context);
  }
}

export class KeyedRead extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public key: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitKeyedRead(this, context);
  }
}

export class SafeKeyedRead extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public key: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitSafeKeyedRead(this, context);
  }
}

/** Possible types for a pipe. */
export enum BindingPipeType {
  /**
   * Pipe is being referenced by its name, for example:
   * `@Pipe({name: 'foo'}) class FooPipe` and `{{123 | foo}}`.
   */
  ReferencedByName,

  /**
   * Pipe is being referenced by its class name, for example:
   * `@Pipe() class FooPipe` and `{{123 | FooPipe}}`.
   */
  ReferencedDirectly,
}

export class BindingPipe extends ASTWithName {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public exp: AST,
    public name: string,
    public args: AST[],
    readonly type: BindingPipeType,
    nameSpan: AbsoluteSourceSpan,
  ) {
    super(span, sourceSpan, nameSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitPipe(this, context);
  }
}

export class LiteralPrimitive extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public value: string | number | boolean | null | undefined,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitLiteralPrimitive(this, context);
  }
}

export class LiteralArray extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expressions: AST[],
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitLiteralArray(this, context);
  }
}

export class SpreadElement extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    readonly expression: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitSpreadElement(this, context);
  }
}

export interface LiteralMapPropertyKey {
  kind: 'property';
  key: string;
  quoted: boolean;
  span: ParseSpan;
  sourceSpan: AbsoluteSourceSpan;
  isShorthandInitialized?: boolean;
}

export interface LiteralMapSpreadKey {
  kind: 'spread';
  span: ParseSpan;
  sourceSpan: AbsoluteSourceSpan;
}

export type LiteralMapKey = LiteralMapPropertyKey | LiteralMapSpreadKey;

export class LiteralMap extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public keys: LiteralMapKey[],
    public values: AST[],
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitLiteralMap(this, context);
  }
}

export class Interpolation extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public strings: string[],
    public expressions: AST[],
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitInterpolation(this, context);
  }
}

export type AssignmentOperation =
  | '='
  | '+='
  | '-='
  | '*='
  | '/='
  | '%='
  | '**='
  | '&&='
  | '||='
  | '??=';
type BinaryOperation =
  | AssignmentOperation
  // Logical
  | '&&'
  | '||'
  | '??'
  // Equality
  | '=='
  | '!='
  | '==='
  | '!=='
  // Relational
  | '<'
  | '>'
  | '<='
  | '>='
  | 'in'
  | 'instanceof'
  // Additive
  | '+'
  | '-'
  // Multiplicative
  | '*'
  | '%'
  | '/'
  // Exponentiation
  | '**';

export class Binary extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public operation: BinaryOperation,
    public left: AST,
    public right: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitBinary(this, context);
  }

  static isAssignmentOperation(op: string): op is AssignmentOperation {
    return (
      op === '=' ||
      op === '+=' ||
      op === '-=' ||
      op === '*=' ||
      op === '/=' ||
      op === '%=' ||
      op === '**=' ||
      op === '&&=' ||
      op === '||=' ||
      op === '??='
    );
  }
}

/**
 * For backwards compatibility reasons, `Unary` inherits from `Binary` and mimics the binary AST
 * node that was originally used. This inheritance relation can be deleted in some future major,
 * after consumers have been given a chance to fully support Unary.
 */
export class Unary extends Binary {
  // Redeclare the properties that are inherited from `Binary` as `never`, as consumers should not
  // depend on these fields when operating on `Unary`.
  override left: never = null as never;
  override right: never = null as never;
  override operation: never = null as never;

  /**
   * Creates a unary minus expression "-x", represented as `Binary` using "0 - x".
   */
  static createMinus(span: ParseSpan, sourceSpan: AbsoluteSourceSpan, expr: AST): Unary {
    return new Unary(
      span,
      sourceSpan,
      '-',
      expr,
      '-',
      new LiteralPrimitive(span, sourceSpan, 0),
      expr,
    );
  }

  /**
   * Creates a unary plus expression "+x", represented as `Binary` using "x - 0".
   */
  static createPlus(span: ParseSpan, sourceSpan: AbsoluteSourceSpan, expr: AST): Unary {
    return new Unary(
      span,
      sourceSpan,
      '+',
      expr,
      '-',
      expr,
      new LiteralPrimitive(span, sourceSpan, 0),
    );
  }

  /**
   * During the deprecation period this constructor is private, to avoid consumers from creating
   * a `Unary` with the fallback properties for `Binary`.
   */
  private constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public operator: '+' | '-',
    public expr: AST,
    binaryOp: BinaryOperation,
    binaryLeft: AST,
    binaryRight: AST,
  ) {
    super(span, sourceSpan, binaryOp, binaryLeft, binaryRight);
  }

  override visit(visitor: AstVisitor, context: any = null): any {
    if (visitor.visitUnary !== undefined) {
      return visitor.visitUnary(this, context);
    }
    return visitor.visitBinary(this, context);
  }
}

export class PrefixNot extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expression: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitPrefixNot(this, context);
  }
}

export class TypeofExpression extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expression: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitTypeofExpression(this, context);
  }
}

export class VoidExpression extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expression: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitVoidExpression(this, context);
  }
}

export class NonNullAssert extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expression: AST,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitNonNullAssert(this, context);
  }
}

export class Call extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public args: AST[],
    public argumentSpan: AbsoluteSourceSpan,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitCall(this, context);
  }
}

export class SafeCall extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public receiver: AST,
    public args: AST[],
    public argumentSpan: AbsoluteSourceSpan,
  ) {
    super(span, sourceSpan);
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    return visitor.visitSafeCall(this, context);
  }
}

export class TaggedTemplateLiteral extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public tag: AST,
    public template: TemplateLiteral,
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitTaggedTemplateLiteral(this, context);
  }
}

export class TemplateLiteral extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public elements: TemplateLiteralElement[],
    public expressions: AST[],
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitTemplateLiteral(this, context);
  }
}

export class TemplateLiteralElement extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public text: string,
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitTemplateLiteralElement(this, context);
  }
}

export class ParenthesizedExpression extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public expression: AST,
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitParenthesizedExpression(this, context);
  }
}

export class ArrowFunctionIdentifierParameter {
  constructor(
    public name: string,
    public span: ParseSpan,
    public sourceSpan: AbsoluteSourceSpan,
  ) {}
}

export type ArrowFunctionParameter = ArrowFunctionIdentifierParameter; // TODO(crisbeto): also rest parameters?

export class ArrowFunction extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    public parameters: ArrowFunctionParameter[],
    public body: AST,
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitArrowFunction(this, context);
  }
}

export class RegularExpressionLiteral extends AST {
  constructor(
    span: ParseSpan,
    sourceSpan: AbsoluteSourceSpan,
    readonly body: string,
    readonly flags: string | null,
  ) {
    super(span, sourceSpan);
  }

  override visit(visitor: AstVisitor, context?: any) {
    return visitor.visitRegularExpressionLiteral(this, context);
  }
}

/**
 * Records the absolute position of a text span in a source file, where `start` and `end` are the
 * starting and ending byte offsets, respectively, of the text span in a source file.
 */
export class AbsoluteSourceSpan {
  constructor(
    public readonly start: number,
    public readonly end: number,
  ) {}
}

export class ASTWithSource<T extends AST = AST> extends AST {
  constructor(
    public ast: T,
    public source: string | null,
    public location: string,
    absoluteOffset: number,
    public errors: ParseError[],
  ) {
    super(
      new ParseSpan(0, source === null ? 0 : source.length),
      new AbsoluteSourceSpan(
        absoluteOffset,
        source === null ? absoluteOffset : absoluteOffset + source.length,
      ),
    );
  }
  override visit(visitor: AstVisitor, context: any = null): any {
    if (visitor.visitASTWithSource) {
      return visitor.visitASTWithSource(this, context);
    }
    return this.ast.visit(visitor, context);
  }
  override toString(): string {
    return `${this.source} in ${this.location}`;
  }
}

/**
 * TemplateBinding refers to a particular key-value pair in a microsyntax
 * expression. A few examples are:
 *
 *   |---------------------|--------------|---------|--------------|
 *   |     expression      |     key      |  value  | binding type |
 *   |---------------------|--------------|---------|--------------|
 *   | 1. let item         |    item      |  null   |   variable   |
 *   | 2. of items         |   ngForOf    |  items  |  expression  |
 *   | 3. let x = y        |      x       |    y    |   variable   |
 *   | 4. index as i       |      i       |  index  |   variable   |
 *   | 5. trackBy: func    | ngForTrackBy |   func  |  expression  |
 *   | 6. *ngIf="cond"     |     ngIf     |   cond  |  expression  |
 *   |---------------------|--------------|---------|--------------|
 *
 * (6) is a notable exception because it is a binding from the template key in
 * the LHS of a HTML attribute to the expression in the RHS. All other bindings
 * in the example above are derived solely from the RHS.
 */
export type TemplateBinding = VariableBinding | ExpressionBinding;

export class VariableBinding {
  /**
   * @param sourceSpan entire span of the binding.
   * @param key name of the LHS along with its span.
   * @param value optional value for the RHS along with its span.
   */
  constructor(
    public readonly sourceSpan: AbsoluteSourceSpan,
    public readonly key: TemplateBindingIdentifier,
    public readonly value: TemplateBindingIdentifier | null,
  ) {}
}

export class ExpressionBinding {
  /**
   * @param sourceSpan entire span of the binding.
   * @param key binding name, like ngForOf, ngForTrackBy, ngIf, along with its
   * span. Note that the length of the span may not be the same as
   * `key.source.length`. For example,
   * 1. key.source = ngFor, key.span is for "ngFor"
   * 2. key.source = ngForOf, key.span is for "of"
   * 3. key.source = ngForTrackBy, key.span is for "trackBy"
   * @param value optional expression for the RHS.
   */
  constructor(
    public readonly sourceSpan: AbsoluteSourceSpan,
    public readonly key: TemplateBindingIdentifier,
    public readonly value: ASTWithSource | null,
  ) {}
}

export interface TemplateBindingIdentifier {
  source: string;
  span: AbsoluteSourceSpan;
}

export interface AstVisitor {
  /**
   * The `visitUnary` method is declared as optional for backwards compatibility. In an upcoming
   * major release, this method will be made required.
   */
  visitUnary?(ast: Unary, context: any): any;
  visitBinary(ast: Binary, context: any): any;
  visitChain(ast: Chain, context: any): any;
  visitConditional(ast: Conditional, context: any): any;
  /**
   * The `visitThisReceiver` method is declared as optional for backwards compatibility.
   * In an upcoming major release, this method will be made required.
   */
  visitThisReceiver?(ast: ThisReceiver, context: any): any;
  visitImplicitReceiver(ast: ImplicitReceiver, context: any): any;
  visitInterpolation(ast: Interpolation, context: any): any;
  visitKeyedRead(ast: KeyedRead, context: any): any;
  visitLiteralArray(ast: LiteralArray, context: any): any;
  visitLiteralMap(ast: LiteralMap, context: any): any;
  visitLiteralPrimitive(ast: LiteralPrimitive, context: any): any;
  visitPipe(ast: BindingPipe, context: any): any;
  visitPrefixNot(ast: PrefixNot, context: any): any;
  visitTypeofExpression(ast: TypeofExpression, context: any): any;
  visitVoidExpression(ast: TypeofExpression, context: any): any;
  visitNonNullAssert(ast: NonNullAssert, context: any): any;
  visitPropertyRead(ast: PropertyRead, context: any): any;
  visitSafePropertyRead(ast: SafePropertyRead, context: any): any;
  visitSafeKeyedRead(ast: SafeKeyedRead, context: any): any;
  visitCall(ast: Call, context: any): any;
  visitSafeCall(ast: SafeCall, context: any): any;
  visitTemplateLiteral(ast: TemplateLiteral, context: any): any;
  visitTemplateLiteralElement(ast: TemplateLiteralElement, context: any): any;
  visitTaggedTemplateLiteral(ast: TaggedTemplateLiteral, context: any): any;
  visitParenthesizedExpression(ast: ParenthesizedExpression, context: any): any;
  visitArrowFunction(ast: ArrowFunction, context: any): any;
  visitRegularExpressionLiteral(ast: RegularExpressionLiteral, context: any): any;
  visitSpreadElement(ast: SpreadElement, context: any): any;
  visitASTWithSource?(ast: ASTWithSource, context: any): any;
  visitEmptyExpr?(ast: EmptyExpr, context: any): any;
  /**
   * This function is optionally defined to allow classes that implement this
   * interface to selectively decide if the specified `ast` should be visited.
   * @param ast node to visit
   * @param context context that gets passed to the node and all its children
   */
  visit?(ast: AST, context?: any): any;
}

export class RecursiveAstVisitor implements AstVisitor {
  visit(ast: AST, context?: any): any {
    // The default implementation just visits every node.
    // Classes that extend RecursiveAstVisitor should override this function
    // to selectively visit the specified node.
    ast.visit(this, context);
  }
  visitUnary(ast: Unary, context: any): any {
    this.visit(ast.expr, context);
  }
  visitBinary(ast: Binary, context: any): any {
    this.visit(ast.left, context);
    this.visit(ast.right, context);
  }
  visitChain(ast: Chain, context: any): any {
    this.visitAll(ast.expressions, context);
  }
  visitConditional(ast: Conditional, context: any): any {
    this.visit(ast.condition, context);
    this.visit(ast.trueExp, context);
    this.visit(ast.falseExp, context);
  }
  visitPipe(ast: BindingPipe, context: any): any {
    this.visit(ast.exp, context);
    this.visitAll(ast.args, context);
  }
  visitImplicitReceiver(ast: ThisReceiver, context: any): any {}
  visitThisReceiver(ast: ThisReceiver, context: any): any {}
  visitInterpolation(ast: Interpolation, context: any): any {
    this.visitAll(ast.expressions, context);
  }
  visitKeyedRead(ast: KeyedRead, context: any): any {
    this.visit(ast.receiver, context);
    this.visit(ast.key, context);
  }
  visitLiteralArray(ast: LiteralArray, context: any): any {
    this.visitAll(ast.expressions, context);
  }
  visitLiteralMap(ast: LiteralMap, context: any): any {
    this.visitAll(ast.values, context);
  }
  visitLiteralPrimitive(ast: LiteralPrimitive, context: any): any {}
  visitPrefixNot(ast: PrefixNot, context: any): any {
    this.visit(ast.expression, context);
  }
  visitTypeofExpression(ast: TypeofExpression, context: any) {
    this.visit(ast.expression, context);
  }
  visitVoidExpression(ast: VoidExpression, context: any) {
    this.visit(ast.expression, context);
  }
  visitNonNullAssert(ast: NonNullAssert, context: any): any {
    this.visit(ast.expression, context);
  }
  visitPropertyRead(ast: PropertyRead, context: any): any {
    this.visit(ast.receiver, context);
  }
  visitSafePropertyRead(ast: SafePropertyRead, context: any): any {
    this.visit(ast.receiver, context);
  }
  visitSafeKeyedRead(ast: SafeKeyedRead, context: any): any {
    this.visit(ast.receiver, context);
    this.visit(ast.key, context);
  }
  visitCall(ast: Call, context: any): any {
    this.visit(ast.receiver, context);
    this.visitAll(ast.args, context);
  }
  visitSafeCall(ast: SafeCall, context: any): any {
    this.visit(ast.receiver, context);
    this.visitAll(ast.args, context);
  }
  visitTemplateLiteral(ast: TemplateLiteral, context: any) {
    // Iterate in the declaration order. Note that there will
    // always be one expression less than the number of elements.
    for (let i = 0; i < ast.elements.length; i++) {
      this.visit(ast.elements[i], context);

      const expression = i < ast.expressions.length ? ast.expressions[i] : null;
      if (expression !== null) {
        this.visit(expression, context);
      }
    }
  }
  visitTemplateLiteralElement(ast: TemplateLiteralElement, context: any) {}
  visitTaggedTemplateLiteral(ast: TaggedTemplateLiteral, context: any) {
    this.visit(ast.tag, context);
    this.visit(ast.template, context);
  }
  visitParenthesizedExpression(ast: ParenthesizedExpression, context: any) {
    this.visit(ast.expression, context);
  }
  visitArrowFunction(ast: ArrowFunction, context: any): any {
    this.visit(ast.body, context);
  }
  visitRegularExpressionLiteral(ast: RegularExpressionLiteral, context: any) {}
  visitSpreadElement(ast: SpreadElement, context: any) {
    this.visit(ast.expression, context);
  }
  visitEmptyExpr(ast: EmptyExpr, context: any): any {}
  // This is not part of the AstVisitor interface, just a helper method
  visitAll(asts: AST[], context: any): any {
    for (const ast of asts) {
      this.visit(ast, context);
    }
  }
}

// Bindings

export class ParsedProperty {
  public readonly isLiteral: boolean;
  public readonly isLegacyAnimation: boolean;
  public readonly isAnimation: boolean;

  constructor(
    public name: string,
    public expression: ASTWithSource,
    public type: ParsedPropertyType,
    public sourceSpan: ParseSourceSpan,
    readonly keySpan: ParseSourceSpan,
    public valueSpan: ParseSourceSpan | undefined,
  ) {
    this.isLiteral = this.type === ParsedPropertyType.LITERAL_ATTR;
    this.isLegacyAnimation = this.type === ParsedPropertyType.LEGACY_ANIMATION;
    this.isAnimation = this.type === ParsedPropertyType.ANIMATION;
  }
}

export enum ParsedPropertyType {
  DEFAULT,
  LITERAL_ATTR,
  LEGACY_ANIMATION,
  TWO_WAY,
  ANIMATION,
}

export enum ParsedEventType {
  // DOM or Directive event
  Regular,
  // Legacy animation specific event
  LegacyAnimation,
  // Event side of a two-way binding (e.g. `[(property)]="expression"`).
  TwoWay,
  // Animation specific event
  Animation,
}

export class ParsedEvent {
  // Regular events have a target
  // Legacy Animation events have a phase
  constructor(
    name: string,
    targetOrPhase: string | null,
    type: ParsedEventType.TwoWay,
    handler: ASTWithSource<NonNullAssert | PropertyRead | KeyedRead>,
    sourceSpan: ParseSourceSpan,
    handlerSpan: ParseSourceSpan,
    keySpan: ParseSourceSpan,
  );

  constructor(
    name: string,
    targetOrPhase: string | null,
    type: ParsedEventType,
    handler: ASTWithSource,
    sourceSpan: ParseSourceSpan,
    handlerSpan: ParseSourceSpan,
    keySpan: ParseSourceSpan,
  );

  constructor(
    public name: string,
    public targetOrPhase: string | null,
    public type: ParsedEventType,
    public handler: ASTWithSource,
    public sourceSpan: ParseSourceSpan,
    public handlerSpan: ParseSourceSpan,
    readonly keySpan: ParseSourceSpan,
  ) {}
}

/**
 * ParsedVariable represents a variable declaration in a microsyntax expression.
 */
export class ParsedVariable {
  constructor(
    public readonly name: string,
    public readonly value: string,
    public readonly sourceSpan: ParseSourceSpan,
    public readonly keySpan: ParseSourceSpan,
    public readonly valueSpan?: ParseSourceSpan,
  ) {}
}

export enum BindingType {
  // A regular binding to a property (e.g. `[property]="expression"`).
  Property,
  // A binding to an element attribute (e.g. `[attr.name]="expression"`).
  Attribute,
  // A binding to a CSS class (e.g. `[class.name]="condition"`).
  Class,
  // A binding to a style rule (e.g. `[style.rule]="expression"`).
  Style,
  // A binding to a legacy animation reference (e.g. `[animate.key]="expression"`).
  LegacyAnimation,
  // Property side of a two-way binding (e.g. `[(property)]="expression"`).
  TwoWay,
  // A binding to an animation CSS class or function (e.g. `[animate.leave]="expression"`).
  Animation,
}

export class BoundElementProperty {
  constructor(
    public name: string,
    public type: BindingType,
    public securityContext: SecurityContext,
    public value: ASTWithSource,
    public unit: string | null,
    public sourceSpan: ParseSourceSpan,
    readonly keySpan: ParseSourceSpan | undefined,
    public valueSpan: ParseSourceSpan | undefined,
  ) {}
}