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62 lines
1.8 KiB
62 lines
1.8 KiB
// @flow
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import {NumberType, toString} from '../types.js';
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import {typeOf} from '../values.js';
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import RuntimeError from '../runtime_error.js';
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import type {Expression, SerializedExpression} from '../expression.js';
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import type ParsingContext from '../parsing_context.js';
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import type EvaluationContext from '../evaluation_context.js';
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import type {Type} from '../types.js';
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class Length implements Expression {
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type: Type;
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input: Expression;
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constructor(input: Expression) {
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this.type = NumberType;
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this.input = input;
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}
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static parse(args: $ReadOnlyArray<mixed>, context: ParsingContext): ?Length {
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if (args.length !== 2)
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return context.error(`Expected 1 argument, but found ${args.length - 1} instead.`);
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const input = context.parse(args[1], 1);
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if (!input) return null;
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if (input.type.kind !== 'array' && input.type.kind !== 'string' && input.type.kind !== 'value')
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return context.error(`Expected argument of type string or array, but found ${toString(input.type)} instead.`);
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return new Length(input);
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}
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evaluate(ctx: EvaluationContext): any | number {
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const input = this.input.evaluate(ctx);
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if (typeof input === 'string') {
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return input.length;
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} else if (Array.isArray(input)) {
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return input.length;
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} else {
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throw new RuntimeError(`Expected value to be of type string or array, but found ${toString(typeOf(input))} instead.`);
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}
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}
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eachChild(fn: (_: Expression) => void) {
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fn(this.input);
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}
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outputDefined(): boolean {
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return false;
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}
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serialize(): SerializedExpression {
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const serialized = ["length"];
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this.eachChild(child => { serialized.push(child.serialize()); });
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return serialized;
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}
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}
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export default Length;
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