Lexer Struct Template Reference
[Series]

Lexer class for the rational expression parser. More...

List of all members.

Public Types
typedef KRatExpToken< typename Element< S, T >::monoid_elt_value_t, typename Element< S, T >::semiring_elt_value_t >	krat_exp_token_t
typedef std::list< krat_exp_token_t >	token_stream_t
Public Member Functions
	Lexer (bool trace=false)
void	lex_error (const std::string &msg="Lex error.")
	Put the lexer into an error state.
void	lex (const std::string &in, const Element< S, T > &e)
	Perform lexing.
bool	error () const
	Return true when an error occured.
const std::string &	error_msg () const
	Return the error message.
krat_exp_token_t	first () const
	Return the first token.
krat_exp_token_t	second () const
	Return the second token.
void	eat ()
	Shift tokens.
void	set_trace (bool trace)
Protected Attributes
token_stream_t	tokens_
bool	trace_
std::string	error_msg_
bool	error_

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Detailed Description

template<class S, class T>
struct vcsn::algebra::Lexer< S, T >

Lexer class for the rational expression parser.

See also:

Parser

Definition at line 238 of file krat_exp_parser.hxx.

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Member Function Documentation

void lex	(	const std::string &	in,
		const Element< S, T > &	e
	)			[inline]

Perform lexing.

Parameters:

	in	The rational expression to lex, as a string.
	e	The element which will be used later for parsing. It used to guess words and semiring types.

Definition at line 271 of file krat_exp_parser.hxx.

References Lexer::error_, vcsn::misc::escaped(), Lexer::lex_error(), vcsn::parse_weight(), vcsn::parse_word(), KRatExpToken::reset(), Element::structure(), Lexer::tokens_, and vcsn::misc::usual_escaped_characters().

Referenced by vcsn::algebra::parse().

void eat

(

)

[inline]

Shift tokens.

Remove the first token from the token stream. So second becames first, third becames second, and so on...

Definition at line 363 of file krat_exp_parser.hxx.

References Lexer::tokens_, and Lexer::trace_.

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