LEX Question

[T. William Wells]

I have this at the top of one of my .l files:

%{
#undef input
#undef unput
# define input() (((yytchar=yysptr>yysbuf?U(*--yysptr): \
    nextchar())==10?(yylineno++,yytchar):yytchar)==EOF?0:yytchar)
# define unput(c) {yytchar= (c);if(yytchar=='\n')yylineno--; \
    *yysptr++=yytchar;}
%}

[These ugly macros are made from the ones that are created by lex.]

And one of my source files contains this bit of code:

int
nextchar()
{
	if (*Bufptr == 0) {
		return ('\n');
	} else {
		return (*Bufptr++);
	}
}

Replace nextchar with whatever function you need for returning
characters.

It does work, I use the program containing it all the time.  I don't
recall any of the design decisions I made when doing this; what it is
used for is lexing out of a buffer. I do not know if the details will
be applicable to your system. (It works on a Sun and on my Microport
V/386 3.0e).

Consider it as a clue as to what to do.

---
Bill
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