Обсуждение: MSVC build broken with perl 5.10

I just tried the MSVC build on a system with ActiveState Perl 5.10, and
it doesn't work. Some quick debugging before I downgraded to 5.8 showed
that this regexp in Project.pm line 262:   my $replace_re =
qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*: )?\$(\([^\)]+\))\/(.*)\/[^\/]+$};

matches things properly using Perl 5.8 in for example
src/bin/initdb/Makefile (matches a total of around 10 Makefiles), but
in 5.10 it simply does not match anything...

Any perl guru out there who can comment on why? ;-)

//Magnus

Magnus Hagander wrote:
> I just tried the MSVC build on a system with ActiveState Perl 5.10, and
> it doesn't work. Some quick debugging before I downgraded to 5.8 showed
> that this regexp in Project.pm line 262:
>     my $replace_re =
> qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*: )?\$(\([^\)]+\))\/(.*)\/[^\/]+$};
>
> matches things properly using Perl 5.8 in for example
> src/bin/initdb/Makefile (matches a total of around 10 Makefiles), but
> in 5.10 it simply does not match anything...
>
> Any perl guru out there who can comment on why? ;-)
>
>   

Perhaps you would like to comment it using the x format, so that it 
doesn't just look like white noise.

cheers

andrew

Andrew Dunstan wrote:
> 
> 
> Magnus Hagander wrote:
> > I just tried the MSVC build on a system with ActiveState Perl 5.10,
> > and it doesn't work. Some quick debugging before I downgraded to
> > 5.8 showed that this regexp in Project.pm line 262:
> >     my $replace_re =
> > qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*: )?\$(\([^\)]+\))\/(.*)\/[^\/]+$};
> >
> > matches things properly using Perl 5.8 in for example
> > src/bin/initdb/Makefile (matches a total of around 10 Makefiles),
> > but in 5.10 it simply does not match anything...
> >
> > Any perl guru out there who can comment on why? ;-)
> >
> >   
> 
> Perhaps you would like to comment it using the x format, so that it 
> doesn't just look like white noise.

That would be a good idea, no? ;-) I have no idea what you mean with
"using the x format", though, but I agree in general that the
white-noise format is not a good idea...

//Magnus

On Thu, Apr 10, 2008 at 04:12:56PM +0200, Magnus Hagander wrote:
> > >     my $replace_re =
> > > qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*: )?\$(\([^\)]+\))\/(.*)\/[^\/]+$};

> > Perhaps you would like to comment it using the x format, so that it
> > doesn't just look like white noise.
>
> That would be a good idea, no? ;-) I have no idea what you mean with
> "using the x format", though, but I agree in general that the
> white-noise format is not a good idea...

Using x format modifier means you can put comments and whitespace in your regex, like:

my $replace_re = qr{^([^:\n\$]+\.c)    # This matches the filename in $1                   \s*:\s*(?:%\s*:\ )? #
somethigwith a %-sign                  ...etc...                  }x; 
Check the perlre manpage for more info.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Please line up in a tree and maintain the heap invariant while
> boarding. Thank you for flying nlogn airlines.

Magnus Hagander wrote:
> I just tried the MSVC build on a system with ActiveState Perl 5.10,
and
> it doesn't work. Some quick debugging before I downgraded to 5.8
showed
> that this regexp in Project.pm line 262:
>     my $replace_re = qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*:
)?\$(\([^\)]+\))\/(.*)\/[^\/]+$};
>
> matches things properly using Perl 5.8 in for example
> src/bin/initdb/Makefile (matches a total of around 10 Makefiles), but
> in 5.10 it simply does not match anything...
>
> Any perl guru out there who can comment on why? ;-)

The answer is actually simple, the \n needs the multiline modifier,
and thus the m needs to be part of the quote-like operator.

The perl doc states:
    "This operator quotes (and possibly compiles) its STRING"
(it seems 5.8 did not compile, but 5.10 does)

I feel that it is rather not a perl bug, and that the modifiers need to
be put
on the qr{}. I do not quite see why this re needs to be multiline in the
first place,
but I have not touched that in the attached patch, that is ready to
apply.
(modification works in perl 5.6, 5.8, 5.10)

Andreas

Zeugswetter Andreas OSB SD wrote:
> Magnus Hagander wrote:
>
>> I just tried the MSVC build on a system with ActiveState Perl 5.10,
>>
> and
>
>> it doesn't work. Some quick debugging before I downgraded to 5.8
>>
> showed
>
>> that this regexp in Project.pm line 262:
>>     my $replace_re = qr{^([^:\n\$]+\.c)\s*:\s*(?:%\s*:
>>
> )?\$(\([^\)]+\))\/(.*)\/[^\/]+$};
>
>> matches things properly using Perl 5.8 in for example
>> src/bin/initdb/Makefile (matches a total of around 10 Makefiles), but
>> in 5.10 it simply does not match anything...
>>
>> Any perl guru out there who can comment on why? ;-)
>>
>
> The answer is actually simple, the \n needs the multiline modifier,
> and thus the m needs to be part of the quote-like operator.
>
> The perl doc states:
>     "This operator quotes (and possibly compiles) its STRING"
> (it seems 5.8 did not compile, but 5.10 does)
>
> I feel that it is rather not a perl bug, and that the modifiers need to
> be put
> on the qr{}. I do not quite see why this re needs to be multiline in the
> first place,
> but I have not touched that in the attached patch, that is ready to
> apply.
> (modification works in perl 5.6, 5.8, 5.10)
>
>


Thanks, that makes sense. I wonder how it ever worked before. Anyway,
patch applied back as far as 8.2.

cheers

andrew