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Module

std/datetime/tokenizer.ts

Deno standard library
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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
export type Token = { type: string; value: string | number; index: number; [key: string]: unknown;};
export interface ReceiverResult { [name: string]: string | number | unknown;}export type CallbackResult = { type: string; value: string | number; [key: string]: unknown;};type CallbackFunction = (value: unknown) => CallbackResult;
export type TestResult = { value: unknown; length: number } | undefined;export type TestFunction = ( string: string,) => TestResult | undefined;
export interface Rule { test: TestFunction; fn: CallbackFunction;}
export class Tokenizer { rules: Rule[];
constructor(rules: Rule[] = []) { this.rules = rules; }
addRule(test: TestFunction, fn: CallbackFunction): Tokenizer { this.rules.push({ test, fn }); return this; }
tokenize( string: string, receiver = (token: Token): ReceiverResult => token, ): ReceiverResult[] { function* generator(rules: Rule[]): IterableIterator<ReceiverResult> { let index = 0; for (const rule of rules) { const result = rule.test(string); if (result) { const { value, length } = result; index += length; string = string.slice(length); const token = { ...rule.fn(value), index }; yield receiver(token); yield* generator(rules); } } } const tokenGenerator = generator(this.rules);
const tokens: ReceiverResult[] = [];
for (const token of tokenGenerator) { tokens.push(token); }
if (string.length) { throw new Error( `parser error: string not fully parsed! ${string.slice(0, 25)}`, ); }
return tokens; }}