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import type { IParser, Input, Result } from "./core.ts";
/** * Attempt to run "left" parser at first. * If it succeeds, return its result. * If it fails, run "right" parser. * *     or(digit(), alpha())("4").output === "4"; *     or(digit(), alpha())("a").output === "a"; *     or(digit(), alpha())("").ok === false; * * @param left left parser * @param right right parser */export function or<L, R, E, I extends Input, CtxIn, CtxOut>(  left: IParser<L, unknown, I, CtxIn, CtxOut>,  right: IParser<R, E, I, CtxIn, CtxOut>,): IParser<L | R, E, I, CtxIn, CtxOut> {  function parse<C extends CtxIn>(    input: I,    context: C = Object.create(null),  ): Result<I, L | R, E, C & CtxOut> {    const result = left(input, context);    if (result.ok) {      return result;    } else {      return right(input, context);    }  }  parse.left = left;  parse.right = right;
  return parse;}
type ChoiceOutput<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = P[number] extends IParser<infer O, infer _, I, infer _, infer _> ? O  : never;type ChoiceError<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = P[number] extends IParser<infer _, infer E, I, infer _, infer _> ? E  : never;type ChoiceCtxIn<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = P[number] extends IParser<infer _, infer _, I, infer C, infer _> ? C  : never;type ChoiceCtxOut<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = P[number] extends IParser<infer _, infer _, I, infer _, infer C> ? C  : never;type ChoiceParser<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = IParser<  ChoiceOutput<I, P>,  ChoiceError<I, P>,  I,  ChoiceCtxIn<I, P>,  ChoiceCtxOut<I, P>>;type ChoiceResult<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],> = Result<  I,  ChoiceOutput<I, P>,  ChoiceError<I, P>,  ChoiceCtxIn<I, P> & ChoiceCtxOut<I, P>>;
/** * Attempt to run each parser of a list of parsers. * Once a parser succeeds, return its result. * If no parsers succeed, return last result. * *     const parser = choice(char("-"), char("+"), char(".")); *     parser("-").output === "-"; *     parser("+").output === "+"; *     parser(".").output === "."; *     parser("").ok === false; * * @param parsers Alternative parsers. Order is insensitive. */export function choice<  P extends readonly IParser<unknown, unknown, string, unknown, unknown>[],>(  ...parsers: P): ChoiceParser<string, P>;/** * Attempt to run each parser of a list of parsers. * Once a parser succeeds, return its result. * If no parsers succeed, return last result. * *     const parser = choice(byte(1), byte(2), byte(3)); *     parser(Uint8Array.of(1)).output === 1; *     parser(Uint8Array.of(2)).output === 2; *     parser(Uint8Array.of(3)).output === 3; *     parser(Uint8Array.of()).ok === false; * * @param parsers Alternative parsers. Order is insensitive. */export function choice<  P extends readonly IParser<unknown, unknown, Uint8Array, unknown, unknown>[],>(...parsers: P): ChoiceParser<Uint8Array, P>;export function choice<  I extends Input,  P extends readonly IParser<unknown, unknown, I, unknown, unknown>[],>(...parsers: P): ChoiceParser<I, P> {  function parse<C extends ChoiceCtxIn<I, P>>(    input: I,    context: C = Object.create(null),  ): ChoiceResult<I, P> {    const { parsers } = parse;    const lastIndex = parsers.length - 1;    for (let i = 0; i < lastIndex; i += 1) {      const result = parsers[i](input, context);      if (result.ok) {        return result as ChoiceResult<I, P>;      }    }
    return parsers[lastIndex](input, context) as ChoiceResult<I, P>;  }  parse.parsers = parsers;
  return parse as ChoiceParser<I, P>;}