[9fans] rc for unix

[9fans] rc for unix

[Boyd Roberts]

It's at:

    http://www.star.le.ac.uk/~tjg/rc

With the fixed =.c called history.c:

/*
	history.c -- primitive history mechanism

	Paul Haahr & Byron Rakitzis, July 1991.

	This program mimics the att v8 = and == history programs.
	The edit() algorithm was adapted from a similar program
	that Boyd Roberts wrote, but otherwise all the code has
	been written from scratch.

	edit() was subsequently redone by Hugh Redelmeier in order
	to correctly deal with tab characters in the source line.

	BUGS:
	There is an implicit assumption that commands are no
	more than 1k characters long.
*/

The question is whether I can stand another shell game [change] ...

Re: [9fans] rc for unix

[Thomas Bushnell, BSG]

boyd@strakt.com (Boyd Roberts) writes:

> 	Paul Haahr & Byron Rakitzis, July 1991.
>       ...
> 	BUGS:
> 	There is an implicit assumption that commands are no
> 	more than 1k characters long.

You'd think by 1991 poeple would have stopped making such
assumptions...

Re: [9fans] rc for unix

[Boyd Roberts]

"Thomas Bushnell, BSG" wrote:
> >       BUGS:
> >       There is an implicit assumption that commands are no
> >       more than 1k characters long.
>
> You'd think by 1991 poeple would have stopped making such
> assumptions...

Exactly.

The original code didn't care, until you ran out of memory:

#define FLEXZ       128

#define flex_char(f, c)  (*((f)->f_ptr == (f)->f_end ? flex_fill(f) :
(f)->f_ptr++) = (c))

typedef struct
{
     char *f_str;
     char *f_end;
     char *f_ptr;
}
          flex;

void
flex_init(f)
register flex  *f;
{
     f->f_str = f->f_ptr = salloc(FLEXZ);
     f->f_end = f->f_ptr + FLEXZ;
}

char *
flex_fill(f)
register flex  *f;
{
     register int   s;

     s = f->f_end - f->f_str + FLEXZ;

     f->f_str = srealloc(f->f_str, s);
     f->f_end = f->f_str + s;
     f->f_ptr = f->f_end - FLEXZ;

     return f->f_ptr++;
}

...

You get the picture.