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Postings from June 2022
Karl Williamson <public@khwilliamson.com> wrote:
:On 6/28/22 20:27, hv@crypt.org wrote:
:> Karl Williamson <public@khwilliamson.com> wrote:
:> : Then the loop innards would look like:
:> :
:> : while (s < e) {
:> : code_point = next_uvchr(s, e, &retlen);
:> :
:> : if (retlen < 0) {
:>
:> I'd recommend making this `if (retlen <= 0) {` or otherwise handling
:> the retlen == 0 case, even if you only expect that when s >= e: the
:> function should be capable of doing something reasonable on an empty
:> string, which probably means not croaking.
:>
:> : ... process error ...
:> : retlen = -retlen;
:> : }
:
:It is currently illegal to call the existing functions with zero length
:input. The functions don't now croak on zero length input, but they do
:assert against it, which on DEBUGGING builds is pretty much the same thing.
Ok, let's hope module writers habitually develop with a debug build.
And in another reply:
:The main difference would be that the return code doesn't have to be
:disambiguated. Right now you can't tell whether the input was a NUL
:character or an error, without testing each return. cpan modules don't
:tend to do this, leaving them vulnerable. This API is so that you can
:be naive and still be safe.
How naive do you want? Anyone that fails to check for negative retlen
can fail quite unsafely.
I think we've established in previous discussion that you are more
comfortable with this sort of overloaded interface than I am, so I
do not wish to belabour the point. But this does rather remind me of
https://github.com/Perl/perl5/issues/14498, where pretty much every
use of grok_atou in core was buggy. I do recommend reading through
that discussion again to see if there's stuff worth learning that
could be applicable to this API.
Hugo
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