fcppt.parse

Description

Library for parsers.

Link to fcppt_parse_interface.

Introduction

Introduction

In a broad sense, a parser gets a string as input and if it belongs to a certain language, produces a specific output. For example, suppose we want to parse numbers of the form [0-9]*, where we allow multiple leading zeroes for simplicity. Each word that belongs to this language should produce a word over the alphabet {0,...,9}. To encode this in C++, we start with an enum of the form

enum class digit
{
  _0,
  _1,
  _2,
  _3,
  _4,
  _5,
  _6,
  _7,
  _8,
  _9
};

Next, we create a function that given char c and digit d, it produces a parser that returns d if and only if it gets c as input:

auto make_digit(char const c, digit const d)
{
  return fcppt::parse::convert_const{fcppt::parse::literal{c}, fcppt::copy(d)};
}

Parser definition

A parser is an object with the following properties:

• It inherits from fcppt::parse::tag.
• It has a typedef result_type.
• It has a member function

  template<typename Ch, typename Skipper>
  fcppt::parse::result<Ch, result_type>
  parse(fcppt::reference<fcppt::parse::basic_stream<Ch>>, Skipper const &) const

Classes
class	fcppt::parse::alternative< Left, Right >
	Tries two parsers in succession. Uses the result of the first one that does not fail. More...

Typedefs
template<typename Left , typename Right >
using	fcppt::parse::alternative_result = fcppt::parse::detail::alternative_result< fcppt::metal::unique< ::metal::join< fcppt::parse::detail::alternative_list< Left >, fcppt::parse::detail::alternative_list< Right > > > >
	The result type of an alternative parser. More...

Functions
template<typename Result , typename Parser >
fcppt::parse::convert< fcppt::type_traits::remove_cv_ref_t< Parser >, Result >	fcppt::parse::as_struct (Parser &&_parser)
	Creates a parser that converts a tuple into a struct. More...

Typedef Documentation

alternative_result

template<typename Left , typename Right >

using fcppt::parse::alternative_result = typedef fcppt::parse::detail::alternative_result< fcppt::metal::unique< ::metal::join< fcppt::parse::detail::alternative_list< Left >, fcppt::parse::detail::alternative_list< Right > > > >

The result type of an alternative parser.

TODO

Function Documentation

as_struct()

template<typename Result , typename Parser >

fcppt::parse::convert< fcppt::type_traits::remove_cv_ref_t< Parser >, Result> fcppt::parse::as_struct

(

Parser &&

_parser

)

Creates a parser that converts a tuple into a struct.

Template Parameters

Parser

A parser whose result is a std::tuple.