code: public final <R> Parser<R> map(final Function<? super T, ? extends R> map) {
      return new Parser<R>() {
        @Override boolean apply(final ParseContext ctxt) {
          final boolean r = Parser.this.apply(ctxt);
          if (r) {
            ctxt.result = map.apply(Parser.this.getReturn(ctxt));
          }
          return r;
        }
        @Override public String toString() {
          return map.toString();
        }
      };
    }
docs: A {@link Parser} that runs {@code this} parser and transforms the return value using {@code map}.