From: Ingo Schwarze <schwarze@usta.de>
To: Kristaps Dzonsons <kristaps@bsd.lv>
Cc: tech@mdocml.bsd.lv
Subject: Re: Division by zero
Date: Mon, 20 Oct 2014 15:09:32 +0200 [thread overview]
Message-ID: <20141020130932.GA19002@iris.usta.de> (raw)
In-Reply-To: <5444DFEC.1040802@bsd.lv>
Hi Kristaps,
Kristaps Dzonsons wrote on Mon, Oct 20, 2014 at 12:11:56PM +0200:
> As enclosed! It also needed "ln" for the line numbering.
OK schwarze@.
> ...or we could just be a bit more realistic and let *res = INT_MAX,
> with sign depending on the numerator. ;)
That would require coordinating with groff, i guess.
I'm not sure it's worth changing.
> (I use *res = 0 now.)
Yes, that's the right way. Get stuff done following traditional
behaviour (unless that is completely crazy), such that progress in
mandoc isn't obstructed by having to coordinate with groff. If a
good reason arises later to change behaviour, that's a different
matter and can be dealt with slowly.
Thanks,
Ingo
> Index: mandoc.h
> ===================================================================
> RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/mandoc.h,v
> retrieving revision 1.163
> diff -u -p -r1.163 mandoc.h
> --- mandoc.h 14 Oct 2014 02:16:06 -0000 1.163
> +++ mandoc.h 20 Oct 2014 10:10:50 -0000
> @@ -166,6 +166,7 @@ enum mandocerr {
> MANDOCERR_IT_NONUM, /* skipping request without numeric argument */
> MANDOCERR_ARG_SKIP, /* skipping all arguments: macro args */
> MANDOCERR_ARG_EXCESS, /* skipping excess arguments: macro ... args */
> + MANDOCERR_DIVZERO, /* divide by zero */
>
> MANDOCERR_FATAL, /* ===== start of fatal errors ===== */
>
> Index: read.c
> ===================================================================
> RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/read.c,v
> retrieving revision 1.91
> diff -u -p -r1.91 read.c
> --- read.c 18 Oct 2014 15:57:34 -0000 1.91
> +++ read.c 20 Oct 2014 10:10:50 -0000
> @@ -211,6 +211,7 @@ static const char * const mandocerrs[MAN
> "skipping request without numeric argument",
> "skipping all arguments",
> "skipping excess arguments",
> + "divide by zero",
>
> "generic fatal error",
>
> Index: roff.c
> ===================================================================
> RCS file: /usr/vhosts/mdocml.bsd.lv/cvs/mdocml/roff.c,v
> retrieving revision 1.232
> diff -u -p -r1.232 roff.c
> --- roff.c 20 Oct 2014 02:33:06 -0000 1.232
> +++ roff.c 20 Oct 2014 10:10:50 -0000
> @@ -186,9 +186,12 @@ static enum rofferr roff_cond_sub(ROFF_
> static enum rofferr roff_ds(ROFF_ARGS);
> static enum rofferr roff_eqndelim(struct roff *,
> char **, size_t *, int);
> -static int roff_evalcond(const char *, int *);
> -static int roff_evalnum(const char *, int *, int *, int);
> -static int roff_evalpar(const char *, int *, int *);
> +static int roff_evalcond(struct roff *r, int,
> + const char *, int *);
> +static int roff_evalnum(struct roff *, int,
> + const char *, int *, int *, int);
> +static int roff_evalpar(struct roff *, int,
> + const char *, int *, int *);
> static int roff_evalstrcond(const char *, int *);
> static void roff_free1(struct roff *);
> static void roff_freereg(struct roffreg *);
> @@ -622,7 +625,7 @@ roff_res(struct roff *r, char **bufp, si
> case 'B':
> npos = 0;
> ubuf[0] = arg_complete &&
> - roff_evalnum(stnam, &npos, NULL, 0) &&
> + roff_evalnum(r, ln, stnam, &npos, NULL, 0) &&
> stnam + npos + 1 == cp ? '1' : '0';
> ubuf[1] = '\0';
> break;
> @@ -1240,7 +1243,7 @@ out:
> * or string condition.
> */
> static int
> -roff_evalcond(const char *v, int *pos)
> +roff_evalcond(struct roff *r, int ln, const char *v, int *pos)
> {
> int wanttrue, number;
>
> @@ -1271,7 +1274,7 @@ roff_evalcond(const char *v, int *pos)
> break;
> }
>
> - if (roff_evalnum(v, pos, &number, 0))
> + if (roff_evalnum(r, ln, v, pos, &number, 0))
> return((number > 0) == wanttrue);
> else
> return(roff_evalstrcond(v, pos) == wanttrue);
> @@ -1300,7 +1303,7 @@ roff_cond(ROFF_ARGS)
>
> r->last->rule = ROFF_el == tok ?
> (r->rstackpos < 0 ? 0 : r->rstack[r->rstackpos--]) :
> - roff_evalcond(*bufp, &pos);
> + roff_evalcond(r, ln, *bufp, &pos);
>
> /*
> * An if-else will put the NEGATION of the current evaluated
> @@ -1466,14 +1469,15 @@ roff_getop(const char *v, int *pos, char
> * or a single signed integer number.
> */
> static int
> -roff_evalpar(const char *v, int *pos, int *res)
> +roff_evalpar(struct roff *r, int ln,
> + const char *v, int *pos, int *res)
> {
>
> if ('(' != v[*pos])
> return(roff_getnum(v, pos, res));
>
> (*pos)++;
> - if ( ! roff_evalnum(v, pos, res, 1))
> + if ( ! roff_evalnum(r, ln, v, pos, res, 1))
> return(0);
>
> /*
> @@ -1495,7 +1499,8 @@ roff_evalpar(const char *v, int *pos, in
> * Proceed left to right, there is no concept of precedence.
> */
> static int
> -roff_evalnum(const char *v, int *pos, int *res, int skipwhite)
> +roff_evalnum(struct roff *r, int ln, const char *v,
> + int *pos, int *res, int skipwhite)
> {
> int mypos, operand2;
> char operator;
> @@ -1509,7 +1514,7 @@ roff_evalnum(const char *v, int *pos, in
> while (isspace((unsigned char)v[*pos]))
> (*pos)++;
>
> - if ( ! roff_evalpar(v, pos, res))
> + if ( ! roff_evalpar(r, ln, v, pos, res))
> return(0);
>
> while (1) {
> @@ -1524,7 +1529,7 @@ roff_evalnum(const char *v, int *pos, in
> while (isspace((unsigned char)v[*pos]))
> (*pos)++;
>
> - if ( ! roff_evalpar(v, pos, &operand2))
> + if ( ! roff_evalpar(r, ln, v, pos, &operand2))
> return(0);
>
> if (skipwhite)
> @@ -1545,6 +1550,12 @@ roff_evalnum(const char *v, int *pos, in
> *res *= operand2;
> break;
> case '/':
> + if (0 == operand2) {
> + mandoc_msg(MANDOCERR_DIVZERO,
> + r->parse, ln, *pos, v);
> + *res = 0;
> + break;
> + }
> *res /= operand2;
> break;
> case '%':
> @@ -1719,7 +1730,7 @@ roff_nr(ROFF_ARGS)
> if ('+' == sign || '-' == sign)
> val++;
>
> - if (roff_evalnum(val, NULL, &iv, 0))
> + if (roff_evalnum(r, ln, val, NULL, &iv, 0))
> roff_setreg(r, key, iv, sign);
>
> return(ROFF_IGN);
--
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prev parent reply other threads:[~2014-10-20 13:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-19 21:02 Kristaps Dzonsons
2014-10-19 21:38 ` Ingo Schwarze
2014-10-20 10:11 ` Kristaps Dzonsons
2014-10-20 13:09 ` Ingo Schwarze [this message]
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