[Flex-help] multiple input buffer problem using yy_scan_string and yypop_buffer_state()

[Georg T. <ge...@te...>]

Hi,

I'm writing a lexer for a project of mine using flex 2.5.33 an ran into 
a problem which could be a bug, a missinterpretation of the docs or my 
simply mistake. Anyhow I need someones advice:

The problem I wanna solve is a lexer for shellscript like 
variable-definitions: Var=Value. I do need the values in some C code. As 
this is supposed tu run under Linux/Unix as well as Windows just 
sourcing the script and reading in the variables isn't an option. 
Additionaly shell quoted characters are allowed. The Values can, but 
need not bee enclosed in single or double quotes, even only parts of 
them and need to be parsed again afterwords for further processing. To 
accomplish this I read in the whole Value-part into a string  (an array 
of char to be exact) and parse this with:

   yypush_buffer_state( yy_scan_string ( &string_buf[0] ));

which works so far. But I failed restoring the previous puffer state using

   yypop_buffer_state();

which is what I do not understand!? Also trying to redefine yywrap or 
calling yyrestart() at locations seeming sensfull did not help. What did 
I miss?

Actually calling

   LastBuffPtr = YY_CURRENT_BUFFER;
   AktBuffPtr = yy_scan_string ( string_buf_ptr );
   yy_switch_to_buffer(AktBuffPtr);

in the first and

   yy_delete_buffer( YY_CURRENT_BUFFER );
   yy_switch_to_buffer( LastBuffPtr );

in the second did the yob! The same is true for the multiple buffer 
examples on 
http://flex.sourceforge.net/manual/Multiple-Input-Buffers.html#Multiple-Input-Buffers 
working on file buffers!

Thanks for your help in advance!   Georg Tenckhoff