On 10/11/10 22:59, Jilles Tjoelker wrote:
What I was thinking of was adding a lineno field to narg instead of to
all command types. The lineno variable would then be set by expand.c. I
think that leads to a smaller patch and it should still give a sensible
value for almost all errors. Downside is a few more int-to-ascii
conversions. A few divisions is not that bad relative to other things
that are done but printf in modern libcs is bloated and slow and might
slow down things measurably.
I made an attempt at this, but managed to keep the printing in one place
by making LINENO a special variable, which is stored in an int and set
in expandarg. When $LINENO is evaluated, the code checks to see if the
variable is LINENO, and if so, converts the value to a string. This is
one simple pointer comparison in the common case in lookupvar:
if (v == &vlineno && v->text == linenovar)
and avoids sprintf in scripts that don't use LINENO.
FreeBSD's code subtracts the function's starting line number in the
parser rather than at run time. I wonder which is best. (FreeBSD
neglects to save and restore the value, so nested function definitions
may lead to incorrect line numbers, but that could be fixed.)
I used this approach in my updated patch, by resetting plinno to 0 in
simplecmd, and restoring it after calling command().
I think this patch will increase dash's code size at least a little,
which is always a consideration here.
The code size varies little: the current limited LINENO support gives an
executable size of 67680 bytes (default configure settings, no libedit,
gcc 4.5.1, CFLAGS=-Os, strip after compilation), my previous patch gives
67688 bytes, my latest patch gives 67704 bytes. I do not think 24 bytes
should be a problem.
I can also look at getting this
into FreeBSD sh.
That would be great.
I will send the updated patch when I can properly test it. Basic testing
shows it works, but more extensive testing fails. As it turns out, this
is unrelated to my changes: current git, unmodified, has a problem:
$ cat test.sh
echo
cat <<_ACEOF
$0 $@
_ACEOF
echo
$ src/dash test.sh wtf
test.sh wtf
ïïïïï
$
I had not noticed it with my earlier patch, because I actually did my
testing with modified 0.5.6.1 sources.
Thanks for the comments.
Cheers,
Harald
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