fcppt::parse::alternative< Left, Right > Class Template Reference

Detailed Description

template<typename Left, typename Right>
class fcppt::parse::alternative< Left, Right >

Tries the left parser, and if that fails also the right parser. Uses the result of the first one that does not fail.

Let l and r be parsers and al = alternative{l,r}. First, al saves the current position pos. Then, al tries the parser l. If it succeeds, then its result is returned. If it returns a fatal error then this error is returned. Otherwise, al backtracks to pos and returns the result of r.

See fcppt::parse::alternative_result for this parser's result type.

Inheritance diagram for fcppt::parse::alternative< Left, Right >:

Public Types
using	result_type

Public Member Functions
	alternative (Left &&, Right &&)
template<typename Ch, typename Skipper>
fcppt::parse::result< Ch, result_type >	parse (fcppt::reference< fcppt::parse::basic_stream< Ch > >, Skipper const &) const

Member Typedef Documentation

result_type

template<typename Left, typename Right>

using fcppt::parse::alternative< Left, Right >::result_type

Initial value:

 fcppt::parse::
      alternative_result<fcppt::parse::result_of<Left>, fcppt::parse::result_of<Right>>

Constructor & Destructor Documentation

alternative()

template<typename Left, typename Right>

fcppt::parse::alternative< Left, Right >::alternative	(	Left &&	,
		Right &&	)

Member Function Documentation

parse()

template<typename Left, typename Right>

template<typename Ch, typename Skipper>

fcppt::parse::result< Ch, result_type > fcppt::parse::alternative< Left, Right >::parse ( fcppt::reference< fcppt::parse::basic_stream< Ch > > , Skipper const &  ) const

nodiscard