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4a288a7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 | // @flow
import {ValueType, NumberType, StringType, array, toString, isValidType, isValidNativeType} from '../types';
import RuntimeError from '../runtime_error';
import {typeOf} from '../values';
import type {Expression} from '../expression';
import type ParsingContext from '../parsing_context';
import type EvaluationContext from '../evaluation_context';
import type {Type} from '../types';
class Slice implements Expression {
type: Type;
input: Expression;
beginIndex: Expression;
endIndex: ?Expression;
constructor(type: Type, input: Expression, beginIndex: Expression, endIndex?: Expression) {
this.type = type;
this.input = input;
this.beginIndex = beginIndex;
this.endIndex = endIndex;
}
static parse(args: $ReadOnlyArray<mixed>, context: ParsingContext) {
if (args.length <= 2 || args.length >= 5) {
return context.error(`Expected 3 or 4 arguments, but found ${args.length - 1} instead.`);
}
const input = context.parse(args[1], 1, ValueType);
const beginIndex = context.parse(args[2], 2, NumberType);
if (!input || !beginIndex) return null;
if (!isValidType(input.type, [array(ValueType), StringType, ValueType])) {
return context.error(`Expected first argument to be of type array or string, but found ${toString(input.type)} instead`);
}
if (args.length === 4) {
const endIndex = context.parse(args[3], 3, NumberType);
if (!endIndex) return null;
return new Slice(input.type, input, beginIndex, endIndex);
} else {
return new Slice(input.type, input, beginIndex);
}
}
evaluate(ctx: EvaluationContext) {
const input = (this.input.evaluate(ctx): any);
const beginIndex = (this.beginIndex.evaluate(ctx): number);
if (!isValidNativeType(input, ['string', 'array'])) {
throw new RuntimeError(`Expected first argument to be of type array or string, but found ${toString(typeOf(input))} instead.`);
}
if (this.endIndex) {
const endIndex = (this.endIndex.evaluate(ctx): number);
return input.slice(beginIndex, endIndex);
}
return input.slice(beginIndex);
}
eachChild(fn: (_: Expression) => void) {
fn(this.input);
fn(this.beginIndex);
if (this.endIndex) {
fn(this.endIndex);
}
}
outputDefined() {
return false;
}
serialize() {
if (this.endIndex != null && this.endIndex !== undefined) {
const endIndex = this.endIndex.serialize();
return ["slice", this.input.serialize(), this.beginIndex.serialize(), endIndex];
}
return ["slice", this.input.serialize(), this.beginIndex.serialize()];
}
}
export default Slice;
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