/ray/src/lib/lex/scannerbase.h File Reference

Implementing Source code location (file/line) representation. More...

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Classes
class	_InternalFlexScannerBase
	Internally used common parts of scanner base classes. More...
struct	_InternalFlexScannerBase::Config
	Scanner base configuration. More...
struct	_InternalFlexScannerBase::LexerInput
	This is interally used instead of FILE* to feed the lexer. More...
struct	_InternalFlexScannerBase::TokenEntry
	Used to store a token (by token buffer). More...
struct	_InternalFlexScannerBase::XYPos
	Represents position in one file for this class, only. (C++-safe). More...
Defines
#define	_LIB_LEX_FLEXSCANNERBASE_H_   1

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Detailed Description

Implementing Source code location (file/line) representation.

Author:

Wolfgang Wieser ] wwieser (a) gmx <*> de [

Contains base class and functionality for flex-based scanners.

In order to use this class, you need to stick to the following procedure.

• Choose a prefix for the scanner name. This needs to identify the scanner (the grammar it uses) and must be unique throughout the whole program. I'll use BLAH here.
• Create a scanner class include file with your class derived from the scanner base class with prefix. This file must include scannerbase.h but define a special symbol before:

   // myscanner.h
   #include <lib/sconfig.h>
   
   #include <lib/lex/location.h>
   #include <lib/sourcepos/sparchive.h>
   
   #define PREFIX_FlexScannerBase BLAH_FlexScannerBase
   #include <lib/lex/scannerbase.h>
   #undef PREFIX_FlexScannerBase
   
   class MyScanner : public BLAH_FlexScannerBase  // Note: prefix
   {
       friend int BLAH_lex(void *);
       // ...
   };
  

• In the flex .ll file, do TWO #include of scannerbase.cc, one in the first and one in the last section (after second %), but supply the same define as above and some more:

   %{
   #define YY_EXTRA_TYPE  class MyScanner*
   // Include for the first time (FLEX_BOTTOM_PART not defined): 
   #include "scannerbase.cc"
   %}
   
   %pointer
   %option 8bit
   %option reentrant
   %option reentrant
   %option stack
   %option prefix="BLAH_"
   
   %%
   ...rules...
   %%
   
   #define PREFIX_FlexScannerBase BLAH_FlexScannerBase
   #define PREFIX_lex BLAH_lex
   #define PREFIX_lex_init BLAH_lex_init
   #define PREFIX_lex_destroy BLAH_lex_destroy
   #define PREFIX_pop_buffer_state BLAH_pop_buffer_state
   #define PREFIX_push_buffer_state BLAH_push_buffer_state
   #define PREFIX_create_buffer BLAH__create_buffer
   #define PREFIX_switch_to_buffer BLAH__switch_to_buffer
   inline void PREFIX_set_extra(PREFIX_FlexScannerBase *arg,yyscan_t scanner)
       {  yyset_extra((MyScanner*)arg,scanner);  }
   // Include for the second time: 
   #define FLEX_BOTTOM_PART
   #include "scannerbase.cc"
  

All this can best be done by copying the test-scanner* code in this directory and base the own scanner on that (using a different prefix).

Definition in file scannerbase.h.

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Define Documentation

#define _LIB_LEX_FLEXSCANNERBASE_H_   1

Definition at line 18 of file scannerbase.h.

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