Hi Akim, I didn't test it, nor did I run it in a debugger.. so there must be
something I'm not seeing.
The placement of the ++ makes it a post increment, so it's incremented after
the statement, so it should not affect the value of k.
It's incrementing values in temp_map, but temp_map is deallocated after the for
loop, so that's why I thought it wasn't doing anything.
for (s = 0; s < nstates; ++s)
{
transitions *sp = states[s]->transitions;
int i;
for (i = sp->num - 1; i >= 0 && TRANSITION_IS_GOTO (sp, i); --i)
{
goto_number k = temp_map[TRANSITION_SYMBOL (sp, i) - ntokens]++;
from_state[k] = s;
to_state[k] = sp->states[i]->number;
}
}
free (temp_map);
I appreciate your efforts and follow up.
--------------------------------------------
On Mon, 12/29/14, Akim Demaille <a...@lrde.epita.fr> wrote:
Subject: Re: set_goto_map() has unintentional ++ operator
To: "Sean Nakasone" <seannakas...@yahoo.com>
Cc: "Bison Help" <help-bison@gnu.org>
Date: Monday, December 29, 2014, 5:29 AM
> Le
21 déc. 2014 à 21:51, Sean Nakasone <seannakas...@yahoo.com>
a écrit :
>
> in
lalr.c
>
> the ++ at
the end of the following line doesn't have a purpose
>
> goto_number k =
temp_map[TRANSITION_SYMBOL(sp, i) - ntokens]++;
>
> it can be
misleading.
hi Sean,
Well, this piece of code is
old, and it does not seem immediate
(to me)
that the ++ is useless :)
from_state = xcalloc (ngotos, sizeof
*from_state);
to_state = xcalloc (ngotos,
sizeof *to_state);
for
(s = 0; s < nstates; ++s)
{
transitions *sp =
states[s]->transitions;
int
i;
for (i = sp->num - 1; i >=
0 && TRANSITION_IS_GOTO (sp, i); --i)
{
goto_number k = temp_map[TRANSITION_SYMBOL (sp, i) -
ntokens]++;
from_state[k] =
s;
to_state[k] =
sp->states[i]->number;
}
}
free (temp_map);
FTR, byacc (beach and bison are forks of a
common ancestor) reads:
from_state = NEW2(ngotos, Value_t);
to_state = NEW2(ngotos, Value_t);
for (sp = first_shift; sp; sp =
sp->next)
{
state1 = sp->number;
for (i =
sp->nshifts - 1; i >= 0; i--)
{
state2 = sp->shift[i];
symbol =
accessing_symbol[state2];
if (ISTOKEN(symbol))
break;
k = temp_map[symbol]++;
from_state[k] = state1;
to_state[k] = state2;
}
}
FREE(temp_map +
ntokens);
it has the same
++.
What
makes you think it is useless? If I remove it, some tests
fail
(they hang), or I can even get a
SEGV.
$ cat input.y
%%
start: end end {} ;
end:
{ } ;
$ ./_build/35s/tests/bison
input.y
./_build/35s/tests/bison: line 28:
87593 Segmentation fault: 11 $PREBISON
"$abs_top_builddir/src/bison"
${1+"$@"}
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