fcppt::parse::basic_stream< Ch > Class Template Reference

Detailed Description

template<typename Ch>
class fcppt::parse::basic_stream< Ch >

The stream class used while parsing.

This class is the base class for all input streams. Semantically, a basic_stream points to an index 0 <= i <= n in a string a_1...a_n of type vector<Ch>. This index is before the next character that will be read, or in case i = n the end of the string is reached.

The position of a stream is an index plus the current line number l and column number c. These can be obtained as follows:

• The current line number l is the number of newline characters plus one between c_1 and c_i (inclusive).
• Let j <= i be the last newline character, or j=0 in case this does not exist. Then the current column number is c = i - j + 1.

An actual implementation would keep track of these numbers when get_char and set_position are called. This is also the reason why std::basic_istream is not used, since implementing this with streambufs alone is impossible.

Public Member Functions
	basic_stream ()
virtual	~basic_stream ()=0
virtual fcppt::optional::object< Ch >	get_char ()=0
	Returns the next character, if possible. If i = n, then the result is nothing. Otherwise, returns c_{i+1} and increments i.
virtual fcppt::parse::position< Ch >	get_position () const =0
	Returns the current position.
virtual void	set_position (fcppt::parse::position< Ch > const &)=0
	Sets the current position.

Constructor & Destructor Documentation

basic_stream()

template<typename Ch >

fcppt::parse::basic_stream< Ch >::basic_stream

(

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~basic_stream()

template<typename Ch >

virtual fcppt::parse::basic_stream< Ch >::~basic_stream ( )

pure virtual

Member Function Documentation

get_char()

template<typename Ch >

virtual fcppt::optional::object< Ch > fcppt::parse::basic_stream< Ch >::get_char ( )

nodiscardpure virtual

Returns the next character, if possible. If i = n, then the result is nothing. Otherwise, returns c_{i+1} and increments i.

get_position()

template<typename Ch >

virtual fcppt::parse::position< Ch > fcppt::parse::basic_stream< Ch >::get_position ( ) const

nodiscardpure virtual

Returns the current position.

set_position()

template<typename Ch >

virtual void fcppt::parse::basic_stream< Ch >::set_position ( fcppt::parse::position< Ch > const & )

pure virtual

Sets the current position.

Note that the position contains line and column numbers. These must be consistent with the string that is currently being read. Therefore, arguments to this function should only be values returned from get_position.