fcppt::parse::optional< Parser > Class Template Reference

Detailed Description

template<typename Parser>
class fcppt::parse::optional< Parser >

Makes a parser optional.

Let p be a parser and let o = optional{p}. First, o saves the current position pos and then tries p. If p succeeds, then its result is returned. Otherwise, o backtracks to pos. If the returned error is fatal, then o also returns it. Otherwise, o returns the empty optional.

Inheritance diagram for fcppt::parse::optional< Parser >:

Public Types
using	result_type = fcppt::optional::object<fcppt::parse::result_of<Parser>>

Public Member Functions
	optional (Parser &&)
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 Parser >

using fcppt::parse::optional< Parser >::result_type = fcppt::optional::object<fcppt::parse::result_of<Parser>>

Constructor & Destructor Documentation

optional()

template<typename Parser >

fcppt::parse::optional< Parser >::optional ( Parser && )

explicit

Member Function Documentation

parse()

template<typename Parser >

template<typename Ch , typename Skipper >

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

nodiscard