From richard at rushlogistics.com  Sat Dec 23 14:57:36 2023
From: richard at rushlogistics.com (Richard Reina)
Date: Sat, 23 Dec 2023 17:57:36 -0500
Subject: [Chicago-talk] What does dollar sign followed by a period represent?
Message-ID: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>


A few years ago I hastily wrote some code that I did not comment very well. In it I found:

?$switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; # match date

Can anyone tell me what $. means?

Thanks for any help.

Richard

From andy at petdance.com  Sat Dec 23 14:59:24 2023
From: andy at petdance.com (Andy Lester)
Date: Sat, 23 Dec 2023 16:59:24 -0600
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
Message-ID: <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>

It?s the current line number.  See ?perldoc perlvar?

> On Dec 23, 2023, at 4:57?PM, Richard Reina <richard at rushlogistics.com> wrote:
> 
> ?
> A few years ago I hastily wrote some code that I did not comment very well. In it I found:
> 
>  $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; # match date
> 
> Can anyone tell me what $. means?
> 
> Thanks for any help.
> 
> Richard
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk


From richard at rushlogistics.com  Sat Dec 23 15:02:18 2023
From: richard at rushlogistics.com (Richard Reina)
Date: Sat, 23 Dec 2023 18:02:18 -0500
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
 <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>
Message-ID: <1703372538.ngk50d8uzkgo00ks@hostingemail.digitalspace.net>

Ahh thank you so very much Andy!
 
?



On Sat, 23 Dec 2023 16:59:24 -0600, Andy Lester <andy at petdance.com> wrote:

It?s the current line number. See ?perldoc perlvar?

> On Dec 23, 2023, at 4:57?PM, Richard Reina wrote:
>
> ?
> A few years ago I hastily wrote some code that I did not comment very well. In it I found:
>
> $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; # match date
>
> Can anyone tell me what $. means?
>
> Thanks for any help.
>
> Richard
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk

_______________________________________________
Chicago-talk mailing list
Chicago-talk at pm.org
https://mail.pm.org/mailman/listinfo/chicago-talk
?

From dcmertens.perl at gmail.com  Sat Dec 23 21:47:04 2023
From: dcmertens.perl at gmail.com (David Mertens)
Date: Sun, 24 Dec 2023 00:47:04 -0500
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <1703372538.ngk50d8uzkgo00ks@hostingemail.digitalspace.net>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
 <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>
 <1703372538.ngk50d8uzkgo00ks@hostingemail.digitalspace.net>
Message-ID: <CA+4ieYWfdd9f04On5NSwNT1PaK9FHOR-K3PawxrwQ3C8_2hfcQ@mail.gmail.com>

When in doubt,

perldoc perlvar

Might give you a faster answer than asking the list. Ymmv. :-)

On Sat, Dec 23, 2023, 5:02?PM Richard Reina <richard at rushlogistics.com>
wrote:

> Ahh thank you so very much Andy!
>
>
>
>
>
> On Sat, 23 Dec 2023 16:59:24 -0600, Andy Lester <andy at petdance.com> wrote:
>
> It?s the current line number. See ?perldoc perlvar?
>
> > On Dec 23, 2023, at 4:57?PM, Richard Reina wrote:
> >
> > ?
> > A few years ago I hastily wrote some code that I did not comment very
> well. In it I found:
> >
> > $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; #
> match date
> >
> > Can anyone tell me what $. means?
> >
> > Thanks for any help.
> >
> > Richard
> > _______________________________________________
> > Chicago-talk mailing list
> > Chicago-talk at pm.org
> > https://mail.pm.org/mailman/listinfo/chicago-talk
>
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk
>
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/chicago-talk/attachments/20231224/436631fe/attachment.html>

From a.r.ferreira at gmail.com  Sun Dec 24 21:02:26 2023
From: a.r.ferreira at gmail.com (Adriano Ferreira)
Date: Sun, 24 Dec 2023 21:02:26 -0800
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <CA+4ieYWfdd9f04On5NSwNT1PaK9FHOR-K3PawxrwQ3C8_2hfcQ@mail.gmail.com>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
 <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>
 <1703372538.ngk50d8uzkgo00ks@hostingemail.digitalspace.net>
 <CA+4ieYWfdd9f04On5NSwNT1PaK9FHOR-K3PawxrwQ3C8_2hfcQ@mail.gmail.com>
Message-ID: <CAEfK6gfnLQEXz90seFrohK8Lp0Tvt6KPKQ=MNGbitoL6MEHCcQ@mail.gmail.com>

"perldoc" has the answer, just like mentioned by Andy and David. And
"perldoc" has a special trick when you want to look up a special variable.

    perldoc -v PerlVar

In the case of $.:

% perldoc -v '$.'
    HANDLE->input_line_number( EXPR )
    $INPUT_LINE_NUMBER
    $NR
    $.      Current line number for the last filehandle accessed.

            Each filehandle in Perl counts the number of lines that have
            been read from it. (Depending on the value of $/, Perl's idea of
            what constitutes a line may not match yours.) When a line is
            read from a filehandle (via "readline()" or "<>"), or when
            "tell()" or "seek()" is called on it, $. becomes an alias to the
            line counter for that filehandle.

            You can adjust the counter by assigning to $., but this will not
            actually move the seek pointer. *Localizing $. will not localize
            the filehandle's line count*. Instead, it will localize perl's
            notion of which filehandle $. is currently aliased to.

            $. is reset when the filehandle is closed, but not when an open
            filehandle is reopened without an intervening "close()". For
            more details, see "I/O Operators" in perlop. Because "<>" never
            does an explicit close, line numbers increase across "ARGV"
            files (but see examples in "eof" in perlfunc).

            You can also use "HANDLE->input_line_number(EXPR)" to access the
            line counter for a given filehandle without having to worry
            about which handle you last accessed.

            Mnemonic: many programs use "." to mean the current line number.


On Sat, Dec 23, 2023 at 9:47?PM David Mertens <dcmertens.perl at gmail.com>
wrote:

> When in doubt,
>
> perldoc perlvar
>
> Might give you a faster answer than asking the list. Ymmv. :-)
>
> On Sat, Dec 23, 2023, 5:02?PM Richard Reina <richard at rushlogistics.com>
> wrote:
>
>> Ahh thank you so very much Andy!
>>
>>
>>
>>
>>
>> On Sat, 23 Dec 2023 16:59:24 -0600, Andy Lester <andy at petdance.com>
>> wrote:
>>
>> It?s the current line number. See ?perldoc perlvar?
>>
>> > On Dec 23, 2023, at 4:57?PM, Richard Reina wrote:
>> >
>> > ?
>> > A few years ago I hastily wrote some code that I did not comment very
>> well. In it I found:
>> >
>> > $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; #
>> match date
>> >
>> > Can anyone tell me what $. means?
>> >
>> > Thanks for any help.
>> >
>> > Richard
>> > _______________________________________________
>> > Chicago-talk mailing list
>> > Chicago-talk at pm.org
>> > https://mail.pm.org/mailman/listinfo/chicago-talk
>>
>> _______________________________________________
>> Chicago-talk mailing list
>> Chicago-talk at pm.org
>> https://mail.pm.org/mailman/listinfo/chicago-talk
>>
>> _______________________________________________
>> Chicago-talk mailing list
>> Chicago-talk at pm.org
>> https://mail.pm.org/mailman/listinfo/chicago-talk
>>
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/chicago-talk/attachments/20231224/67f77b56/attachment.html>

From richard at rushlogistics.com  Tue Dec 26 05:31:42 2023
From: richard at rushlogistics.com (Richard Reina)
Date: Tue, 26 Dec 2023 08:31:42 -0500
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <CAEfK6gfnLQEXz90seFrohK8Lp0Tvt6KPKQ=MNGbitoL6MEHCcQ@mail.gmail.com>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
 <214554ED-2184-4C19-8190-15756691CCCD@petdance.com>
 <1703372538.ngk50d8uzkgo00ks@hostingemail.digitalspace.net>
 <CA+4ieYWfdd9f04On5NSwNT1PaK9FHOR-K3PawxrwQ3C8_2hfcQ@mail.gmail.com>
 <CAEfK6gfnLQEXz90seFrohK8Lp0Tvt6KPKQ=MNGbitoL6MEHCcQ@mail.gmail.com>
Message-ID: <1703597502.tq5j3iw000c48cc8@hostingemail.digitalspace.net>


	


Thank you for the tip.
?



On Sun, 24 Dec 2023 21:02:26 -0800, Adriano Ferreira <a.r.ferreira at gmail.com> wrote:
?
?
"perldoc" has the answer, just like mentioned by Andy and David. And "perldoc" has a special trick when you want to look up a special variable.

?

? ? perldoc -v PerlVar

?

In the case of $.:

?

% perldoc -v '$.'
? ? HANDLE->input_line_number( EXPR )
? ? $INPUT_LINE_NUMBER
? ? $NR
? ? $. ? ? ?Current line number for the last filehandle accessed.

? ? ? ? ? ? Each filehandle in Perl counts the number of lines that have
? ? ? ? ? ? been read from it. (Depending on the value of $/, Perl's idea of
? ? ? ? ? ? what constitutes a line may not match yours.) When a line is
? ? ? ? ? ? read from a filehandle (via "readline()" or "<>"), or when
? ? ? ? ? ? "tell()" or "seek()" is called on it, $. becomes an alias to the
? ? ? ? ? ? line counter for that filehandle.

? ? ? ? ? ? You can adjust the counter by assigning to $., but this will not
? ? ? ? ? ? actually move the seek pointer. *Localizing $. will not localize
? ? ? ? ? ? the filehandle's line count*. Instead, it will localize perl's
? ? ? ? ? ? notion of which filehandle $. is currently aliased to.

? ? ? ? ? ? $. is reset when the filehandle is closed, but not when an open
? ? ? ? ? ? filehandle is reopened without an intervening "close()". For
? ? ? ? ? ? more details, see "I/O Operators" in perlop. Because "<>" never
? ? ? ? ? ? does an explicit close, line numbers increase across "ARGV"
? ? ? ? ? ? files (but see examples in "eof" in perlfunc).

? ? ? ? ? ? You can also use "HANDLE->input_line_number(EXPR)" to access the
? ? ? ? ? ? line counter for a given filehandle without having to worry
? ? ? ? ? ? about which handle you last accessed.

? ? ? ? ? ? Mnemonic: many programs use "." to mean the current line number.

?

?


On Sat, Dec 23, 2023 at 9:47?PM David Mertens <dcmertens.perl at gmail.com> wrote:


When in doubt,
?

perldoc perlvar

?

Might give you a faster answer than asking the list. Ymmv. :-)

?


On Sat, Dec 23, 2023, 5:02?PM Richard Reina <richard at rushlogistics.com> wrote:

Ahh thank you so very much Andy!

?



On Sat, 23 Dec 2023 16:59:24 -0600, Andy Lester <andy at petdance.com> wrote:

It?s the current line number. See ?perldoc perlvar?

> On Dec 23, 2023, at 4:57?PM, Richard Reina wrote:
>
> ?
> A few years ago I hastily wrote some code that I did not comment very well. In it I found:
>
> $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; # match date
>
> Can anyone tell me what $. means?
>
> Thanks for any help.
>
> Richard
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk

_______________________________________________
Chicago-talk mailing list
Chicago-talk at pm.org
https://mail.pm.org/mailman/listinfo/chicago-talk
?
_______________________________________________
Chicago-talk mailing list
Chicago-talk at pm.org
https://mail.pm.org/mailman/listinfo/chicago-talk

_______________________________________________
Chicago-talk mailing list
Chicago-talk at pm.org
https://mail.pm.org/mailman/listinfo/chicago-talk

_______________________________________________
Chicago-talk mailing list
Chicago-talk at pm.org
https://mail.pm.org/mailman/listinfo/chicago-talk



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/chicago-talk/attachments/20231226/d8ddcc68/attachment.html>

From joel.limardo at forwardphase.com  Wed Dec 27 10:22:13 2023
From: joel.limardo at forwardphase.com (J L)
Date: Wed, 27 Dec 2023 12:22:13 -0600
Subject: [Chicago-talk] What does dollar sign followed by a period
 represent?
In-Reply-To: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
References: <1703372256.skeqe1mkkksk8cck@hostingemail.digitalspace.net>
Message-ID: <CAOfjracAD4VJ_ibpG26faTwmxOH-tkn6-76j2-RaZ8C9DLFf5Q@mail.gmail.com>

1. Have code reviews with pass/fail prior to committing code to a release
(yes, scripts should be considered software and as such subject to release
cycles)
2. If you cannot, at first glance, understand a regex during this then,
2.1 Save it using a meaningful variable with qr and then use it
2.2 Use the /x modifier and document it (
https://perldoc.perl.org/perlre#%2Fx-and-%2Fxx )
3. Store metrics on how long your organization spends per quarter/year on
problems like this one and adopt structural practices to reduce/eliminate
them. I have found the #1 waster is failing to use a well tested CPAN
module that does a better job in lieu of barely tested (and, no surprise,
largely undocumented) code that 'promised' to save time.

People are trying to avoid/refactor Perl scripts because they beleive that
six months down the road they will inevitably fall into this type of
problem. The fact is however there have been several ways to avoid it in
the core language available for decades.

On Sat, Dec 23, 2023, 4:57 PM Richard Reina <richard at rushlogistics.com>
wrote:

>
> A few years ago I hastily wrote some code that I did not comment very
> well. In it I found:
>
>  $switch = $. if m!^[0-3]?[0-9]/[0-3]?[0-9]/(?:[0-9]{2})?[0-9]{2}$!; #
> match date
>
> Can anyone tell me what $. means?
>
> Thanks for any help.
>
> Richard
> _______________________________________________
> Chicago-talk mailing list
> Chicago-talk at pm.org
> https://mail.pm.org/mailman/listinfo/chicago-talk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/chicago-talk/attachments/20231227/d9867b82/attachment.html>