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import type { IParser, Input, Result } from "./core.ts";
/** * Construct a parser only when it's needed. * This is useful when building a recursive parser. * *     // We don't call the `parse` method, *     // so the `recursiveParser` won't be constructed. *     lazy(() => recursiveParser()); * * @param fn Function that returns a parser. */export function lazy<O, E, I extends Input>(  fn: () => IParser<O, E, I>,): IParser<O, E, I> {  function parse<C>(    input: I,    context: C = Object.create(null),  ): Result<I, O, E, C> {    parse.parser ??= parse.fn();
    return parse.parser(input, context);  }  parse.fn = fn;  parse.parser = null as IParser<O, E, I> | null;
  return parse;}