CODEWITHSUNDEEP
bisonflex-lexer
user2469202
user2469202

Reputation: 336

How to redirect flex buffer to my buffer

After days of fagging I am still unable to find how can I declare my buffer. how to pass tkinter text to flex

What is the correct way to redirect flex buffer to my buffer? The steps I want to do: 1 - No conditions, no return to original buffer, just permanently redirect buffer from a graphic frontend by calling a function. 2 - Copy text from graphic frontend to my buffer (or even better to direct fely buffer to the frontend buffer) 3 - call yyparse 4 - repeat steps 2 and 3

Perhaps it is enough to declare a simple public function like this:

void setmybuffer(char *ptr)
{
yy_scan_string (char *ptr);
.... // my other stuff to set
}

Afterward I suppose I call it before any flex operation. But when I try to put this declaration into any part of my *.l file I get error

lex.yy.c: In function ‘setmybuffer’:
lex.yy.c:2206:18: error: conflicting types for ‘yy_scan_string’
  YY_BUFFER_STATE yy_scan_string (char *ptr);

What's wrong and what's the way?

Upvotes: 1

Views: 294

Answers (1)

rici
rici

Reputation: 241881

yyscan_string(char *ptr);

is a declaration, so the compiler complains that the function is already declared and with a different return type.

You wanted to call the function:

yyscan_string(ptr);

So you might do something like this:

// This defines the function setmybuffer, which has no return value ("void")
// and a single parameter which is a pointer to a character string ("char *")
void setmybuffer(char *ptr)
{
  // This **calls** the function yy_scan_string, passing it the same pointer 
  // to a character string.
  yy_scan_string (ptr);
  .... // my other stuff to set
}

Note that you're required to free the YY_BUFFER_STATE when you're finished with it. Usually you can simply call:

yy_delete_buffer(YY_CURRENT_BUFFER);

when you are finished with the input (eg. in your <<EOF>> rule). For more complicated use cases, you might need to save the value returned by yyscan_string.

Upvotes: 1

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