[31473] in Perl-Users-Digest
Perl-Users Digest, Issue: 2725 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Dec 16 21:30:20 2009
Date: Wed, 16 Dec 2009 18:29:46 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Wed, 16 Dec 2009 Volume: 11 Number: 2725
Today's topics:
Re: 2-headed strings and RExes <ben@morrow.me.uk>
Closing a DBI instance <tim@johnsons-web.com>
Re: Closing a DBI instance <ben@morrow.me.uk>
Re: FAQ 5.3 How do I count the number of lines in a fil <brian.d.foy@gmail.com>
Re: push integers from strings sln@netherlands.com
Re: push integers from strings sln@netherlands.com
Re: push integers from strings sln@netherlands.com
Re: push integers from strings <jl_post@hotmail.com>
Re: Searching all instances of a pattern across multi-l sln@netherlands.com
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Wed, 16 Dec 2009 23:30:39 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: 2-headed strings and RExes
Message-Id: <v57ov6-o4h1.ln1@osiris.mauzo.dyndns.org>
Quoth Ilya Zakharevich <nospam-abuse@ilyaz.org>:
> On 2009-12-10, Ben Morrow <ben@morrow.me.uk> wrote:
> > There is now. I submitted a patch to add 'qr' overloading to 5.12, which
> > is called when an overloaded object is used on the RHS of =~ or is
> > interpolated into a regex. Since 5.12 has true REGEX SVs, it seemed
> > silly not to have a corresponding 'type-cast' overload.
>
> Ah... This is probably the reason why FreezeThaw is failing its tests
> on 5.11... Whoever added "true REx" SV did not fix the modules broken
> by this change...
Yes. Nick Clark did a lot of rejigging of the SvTYPE assignments. As of
5.10, PVBMs are now implemented as SVt_PVGVs (IMHO this was a mistake,
but it's done now); as of 5.12, RVs are implemented as SVt_IVs (mostly;
some are PVMGs, as they always were) with SvROK set and there is a new
SVt_REGEX used for qr//. There is also a new SVt_BIND, which is
currently unused but is intended for read-only aliases.
As for fixing the modules: with the number of modules on CPAN, this is
impossible. People writing XS modules that grovel around in perl's guts
are expected to keep up with p5p. I believe some effort is made to smoke
CPAN and fix breakages (certainly there was a big push to get the CPAN
smokes clean before 5.10) but in the end p5p can't fix everything.
Ben
------------------------------
Date: Wed, 16 Dec 2009 19:13:28 -0600
From: Tim Johnson <tim@johnsons-web.com>
Subject: Closing a DBI instance
Message-Id: <slrnhiivlq.hbs.tim@bart.johnson.com>
Platform: Red Hat Linux server, perl 5.8.8, mysql ver 5.0.45
FYI: I am an experienced programmer but _not_ a perl programmer.
I am trouble-shooting a problem on this server where mysql connections
do not seem to be closed by cron jobs
Consider the following perl code snippet in a stand-alone script with
executable privileges that is called by cron:
my $data_Source = "DBI:mysql:".$DATABASE .":".$HOSTNAME;
my $dbh = DBI->connect($data_Source,$USERNAME,$PASSWORD)
or die "$DBI::errstr\n";
To properly disconnect, should I not see something like the following:
$dbh->disconnect
somewhere in this script?
TIA
--
Tim
tim@johnsons-web.com
http://www.akwebsoft.com
------------------------------
Date: Thu, 17 Dec 2009 01:59:39 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Closing a DBI instance
Message-Id: <btfov6-gsh1.ln1@osiris.mauzo.dyndns.org>
Quoth tim@johnsons-web.com:
> Platform: Red Hat Linux server, perl 5.8.8, mysql ver 5.0.45
>
> FYI: I am an experienced programmer but _not_ a perl programmer.
What language(s) do you know? It is useful when explaining things to
know which analogies will be useful and which confusing.
> I am trouble-shooting a problem on this server where mysql connections
> do not seem to be closed by cron jobs
>
> Consider the following perl code snippet in a stand-alone script with
> executable privileges that is called by cron:
>
> my $data_Source = "DBI:mysql:".$DATABASE .":".$HOSTNAME;
> my $dbh = DBI->connect($data_Source,$USERNAME,$PASSWORD)
> or die "$DBI::errstr\n";
>
> To properly disconnect, should I not see something like the following:
> $dbh->disconnect
> somewhere in this script?
Not necessarily. $dbh is a DBI::dbh object, and has a DESTROY method
(like a C++ destructor) that will call ->disconnect when the object goes
out of scope. At that point any transactions in prgress will be rolled
back, so you *should* see a ->commit in the appropriate place (assuming
you are using transactions).
Ben
------------------------------
Date: Wed, 16 Dec 2009 15:10:47 -0600
From: brian d foy <brian.d.foy@gmail.com>
Subject: Re: FAQ 5.3 How do I count the number of lines in a file?
Message-Id: <161220091510475551%brian.d.foy@gmail.com>
In article
<48ffe7ef-f5da-4ec4-a7c2-e2e8fa19c201@u36g2000prn.googlegroups.com>,
C.DeRykus <derykus@gmail.com> wrote:
> > 5.3: How do I count the number of lines in a file?
> Wasn't one of these one-liners included once?
>
> perl -lne '}print $.;{' file # Abigail's trick
> perl -lne 'END {print $.}' file
Those seem like worthy additions. I'll add them to my queue.
------------------------------
Date: Wed, 16 Dec 2009 13:19:21 -0800
From: sln@netherlands.com
Subject: Re: push integers from strings
Message-Id: <mhjii5tesli1o4ntaoulgblhrpkcle2aoe@4ax.com>
On Tue, 15 Dec 2009 20:27:37 -0500, monkeys paw <user@example.net> wrote:
>Following code has quoted numbers in it, but i want
>just integers. What's easiest way?
>
[snip]
> push @allnums, $numstr;
^^
1*$numstr;
This works because of context, didn't read other responces
which I will later.
-sln
------------------------------
Date: Wed, 16 Dec 2009 13:53:40 -0800
From: sln@netherlands.com
Subject: Re: push integers from strings
Message-Id: <jikii59rbe1tkp6u76dh03vk4ps058r5rk@4ax.com>
On Wed, 16 Dec 2009 00:54:09 -0500, monkeys paw <user@example.net> wrote:
>John Bokma wrote:
>> monkeys paw <user@example.net> writes:
>>
>>> Following code has quoted numbers in it, but i want
>>> just integers. What's easiest way?
>>
>>> } else {
>>> push @allnums, $numstr;
>>
>> push @allnums,$numstr * 1
>>
>>> }
>>> }
>>
>> Note that instead of
>>
>>> my
>
>
>Users enter it this way, if i changed the string
>as you suggest i guess i could use an eval:
>
>$nums ='30-32,34,50,54-56';
>$nums =~ s/\-/\s\.\.\s/; # Spaces important
>
>now $nums = 30 .. 32,34,50,54 .. 156
>
>How could i eval $nums into an array so it
>would equal 30,31,32,34, etc...
>
>eval { @allnums = $nums }; # This definitely won't work
>
>>
>> and processing this, you could do:
>>
>> my @allnums = (30..32,34,50,54..56);
>>
>> if you're just looking for an easier notation.
>>
Eval would work. If you don't care about validation,
I guess you could do it a couple of ways:
use strict;
use warnings;
my $input = '30-32,34,50,54-56';
$input =~ s/-/../g;
#my @allnums;
#push @allnums, eval $input;
# or
my @allnums = (eval $input);
use Data::Dumper;die 'DDDEBUG' . Dumper(\@allnums);
__END__
DDDEBUG$VAR1 = [
30,
31,
32,
34,
50,
54,
55,
56
];
-sln
------------------------------
Date: Wed, 16 Dec 2009 14:19:55 -0800
From: sln@netherlands.com
Subject: Re: push integers from strings
Message-Id: <ovmii59jed7mm083t5r05l70kemjb17hjm@4ax.com>
On Wed, 16 Dec 2009 13:53:40 -0800, sln@netherlands.com wrote:
>On Wed, 16 Dec 2009 00:54:09 -0500, monkeys paw <user@example.net> wrote:
>
>my @allnums = (eval $input);
^^
Note that eval's can execute code, so user input can cause harm:
my $input = 'print "shit happens\n";30-32,34,50,54-56';
my @allnums = (eval $input);
*> shit happens
-sln
------------------------------
Date: Wed, 16 Dec 2009 16:24:48 -0800 (PST)
From: "jl_post@hotmail.com" <jl_post@hotmail.com>
Subject: Re: push integers from strings
Message-Id: <4f93cb2c-3dd1-47d8-91f4-e09eb46ec60a@u18g2000pro.googlegroups.com>
On Dec 15, 6:27=A0pm, monkeys paw <u...@example.net> wrote:
> Following code has quoted numbers in it, but i want
> just integers. What's easiest way?
>
> # Translate the var $nums into an integer list
>
> use strict;
> my @allnums;
> my $nums =3D'30-32,34,50,54-56';
> my @nums =3D split /,/, $nums;
>
> for my $numstr (@nums) {
> =A0 =A0 =A0if ($numstr =3D~ /-/) {
> =A0 =A0 =A0 =A0 my ($lower, $upper) =3D split /-/, $numstr ;
> =A0 =A0 =A0 =A0 for my $anum ($lower .. $upper) {
> =A0 =A0 =A0 =A0 =A0 =A0 push @allnums, $anum;
> =A0 =A0 =A0 =A0 }
> =A0 =A0 =A0} else {
> =A0 =A0 =A0 =A0 =A0 =A0 push @allnums, $numstr;
> =A0 =A0 =A0}
>
> }
>
> use Data::Dumper;die 'DDDEBUG' . =A0Dumper(\@allnums);
>
> #Numbers 34 and 50 below have quote around them but i dont want it.
>
> DDDEBUG$VAR1 =3D [
> =A0 =A0 =A0 =A0 =A0 =A030,
> =A0 =A0 =A0 =A0 =A0 =A031,
> =A0 =A0 =A0 =A0 =A0 =A032,
> =A0 =A0 =A0 =A0 =A0 =A0'34',
> =A0 =A0 =A0 =A0 =A0 =A0'50',
> =A0 =A0 =A0 =A0 =A0 =A054,
> =A0 =A0 =A0 =A0 =A0 =A055,
> =A0 =A0 =A0 =A0 =A0 =A056
> =A0 =A0 =A0 =A0 =A0];
The easy answer is to say: Don't use Data::Dumper. There's no way
to tell if a number is a string (or rather, it's difficult) if you
don't use Data::Dumper;
Rewrite your die() line like this:
die "DDDEBUG: @allnums\n";
Seriously, apart from using Data::Dumper, there is pretty much no
simple or straightforward way to tell if a number is a string. Your
code won't even know. So you won't have to worry about if your code
will fail with a "stringed" number, as all strings that can be numbers
are converted seamlessly when used as a number.
But if you still want Data::Dumper to refuse to see the number as a
string, you can use this line:
$_ +=3D 0 foreach @allnums; # "numerate" each element
Remember, unless you print out Data::Dumper's output, your program
won't behave any differently with that line or without. And since you
seem to be using Data::Dumper just for inspection purposes, there
doesn't seem to be any reason to "numerate" your strings.
So I have to ask: Why is it so important that Data::Dumper not
return the numbers as strings, when the rest of Perl can't even tell?
-- Jean-Luc
------------------------------
Date: Wed, 16 Dec 2009 12:29:07 -0800
From: sln@netherlands.com
Subject: Re: Searching all instances of a pattern across multi-lines
Message-Id: <kefii5tjb7l8u7n69nprd6ucomk4msvcmo@4ax.com>
On Sun, 13 Dec 2009 15:43:13 -0800, sln@netherlands.com wrote:
>On Sun, 13 Dec 2009 13:22:15 -0800 (PST), laredotornado <laredotornado@zipmail.com> wrote:
>
>>Hi,
>>
>>I'm using Perl 5.8.8 on Mac 10.5.6. I found this script online for
>>matching a pattern across multiple lines. The problem is, it only
>>prints out one instance of the expression, and I would like it to
>>print out all instances. What can I change so that it will print out
>>all instances?
>>
>>
>>#!/usr/bin/perl
>>use strict;
>>use warnings;
>>
>>open(my $file, "<", "myfile.txt")
>> or die "Can't open file: $!";
>>my $text = do { local $/; <$file> };
>>
>>if ($text =~ /(<\s*script[^<]*>.*?<\/script>)/gs) {
>> print $1;
>>}
>>
>>
>>
>>Thanks, - Dave
>
>'while()' should work as others have said.
>
>The above regex should take into account these forms:
> <tag>
> <tag/>
> <tag attr> content </tag>
> <tag attr/>
>
>Try this. It takes into account all the above forms
>plus handles attributes fairly well, without the need for
>[^<]*, where the actual character '<' can exist in the value
>part. Handling attrib/vals correctly and taking acccount of all
>valid forms are important, it all goes toward partitioning the
>data.
>
>Also, this is a complex parse. It includes multiple atomic
>markup units, which is debatably <tag> style and content.
>Content being the current state that is not markup.
>Ideally, the unit is parsed to find the start element 'script',
>recording is turned on, then off at the end element 'script'.
>
>As it is now, the regex you are using won't correctly parse the
>$text string below.
>
Late addition:
But alas, no simple regex is going to handle nesting correctly
unless there is recursion. Below handles recursive tags, but
requires Perl 5.10 or better.
usage: html_rx.pl [<tag name> [file name]] - default, if no params
Cmd line examples:
*> html_rx.pl form junk.html - Finds 'form' blocks in html file
*> html_rx.pl script junk.html - Finds 'script' blocks in html file
*> html_rx.pl "(?i)script|object" junk.html
- Finds either 'script' or 'object' blocks, case insensitive
(good little markups will be properly nested, ie. those that have terminators)
-sln
-------------
*> perl html_rx.pl "(?i)script|object"
File name: __DATA__
Tag name: (?i)script|object
-------------------- ** type 1
<script attr = "asdf" attr = 'wafsd' />
-------------------- ** type 2
<script>
use strict;
use warnings;
print "hello world, I'm a <tag>\n";
<script a = "it's" b= 'terminated'/>
<object></object>
<script>
// comment me out c++ style
/* now c style
*/
</script>
</script>
-------------------- ** type 1
<script />
====================
Summary
File name: __DATA__
Tag name: (?i)script|object
type1 <tag, tag-attr /> = 2
type2 <tag, tag-attr>..</tag> = 1
*>
-------------
## html_rx.pl
## -sln
use strict;
use warnings;
require 5.010_000;
# usage: html_rx.pl [<tag name> [file name]]
# ---------------------------------------------
my ($tag,$fname) = @ARGV;
my $text;
$tag = 'script' unless defined $tag;
if (defined $fname) {
open my $fh, '<', $fname or die "Can't open file '$fname' : $!";
$text = join '',<$fh>;
close $fh;
} else {
$fname = '__DATA__';
$text = join '',<DATA>;
}
my ($terminated, $open, $close) =
(
qr {< (?:$tag) (?:\s+[^>]*)? />}x,
qr {< (?:$tag) (?:\s+[^>]*? \s*[^/]> | \s*>) }x,
qr {</ (?:$tag) \s*> }x
);
my $rx = qr {
(
(?: $terminated ) # <tag [attr] />
)
| # OR ...
(
(?: $open ) # <tag [attr] >
(?:
(?: (?!$open|$close) . )++ # possessive
|
(?2) # recurse group 2
)*
(?: $close ) # </tag>
)
}xs;
print "\n",<<INFO;
File name: $fname
Tag name: $tag\n
INFO
my ($cnt1,$cnt2) = (0,0);
while ( $text =~ /$rx/g) {
print '-'x20;
if (defined $1) {
print " ** type 1\n",$1,"\n" ;
$cnt1++;
} else {
print " ** type 2\n",$2,"\n" ;
$cnt2++;
}
}
print "\n",'='x20,"\nSummary\n",<<SUMMARY;
File name: $fname
Tag name: $tag
type1 <tag, tag-attr /> = $cnt1
type2 <tag, tag-attr>..</tag> = $cnt2\n
SUMMARY
__DATA__
<script attr = "asdf" attr = 'wafsd' />
</script>
<script>
<script>
<script>
use strict;
use warnings;
print "hello world, I'm a <tag>\n";
<script a = "it's" b= 'terminated'/>
<object></object>
<script>
// comment me out c++ style
/* now c style
*/
</script>
</script>
<script>
<script />
<notme>
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V11 Issue 2725
***************************************
