Re: yy_scan_string

[Luca]

never2di ha scritto:
> I'm a newbie to Bison + Flex. and I'm having trouble in getting
> yy_scan_string to work. I have tried the following
>
> YY_BUFFER_STATE my_string_buffer = yy_scan_string(my_string);
> yyparse();
> yy_delete_buffer(my_string_buffer );
>
> the parser errors out with a syntax error at the first token. I have
> verified that the grammar and the content of 'my_string' works using
> yyrestart(yyin) and also with yy_create_buffer() through a file.
>
> Is there something special state that I have to set flex in before I call
> yyparse()? 
> if not what is that I'm doing wrong and what needs to be done?
>
> bison (GNU Bison) 2.4  
>
> Thanks :handshake:
>
>
>
>   
      

The problem concerns Flex and not Bison.
I anyway think you're right, you have to call yy_switch_to_buffer;
the following code should be right:

YY_BUFFER_STATE b=yy_scan_string(my_string);
yy_switch_to_buffer(b);       //buffer change
yyparse();   
yylex_destroy();             //to avoid leakage

You can read how "Multiple Input Buffers" works in flex help:
http://flex.sourceforge.net/manual/Multiple-Input-Buffers.html#Multiple-Input-Buffers

Luca