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However, you might consider asking in the chatterbox first (if you're a
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Hi Perl Monks, I have what is hopefully a simple question, but one I have been unable to search for due to the odd syntax of the below.
The program I'm working on has a core requirement to work on older systems, and has a cutoff of Perl 5.008 (selected because Redhat mid 2000s release was quite late to support 5.010) or newer, though that could change in the future to either a touch earlier version, or a touch later version (but certainly never newer as max oldest than 5.010). As an aside, so far Perl 5.x has far exceeded my wildest expectations in this regard, the program is in fact working on everything! No matter how weird or arcane.
my $a='3.4.4'; my $c = () = $a =~ /\./g; print "$c\n"
However, my question is this: when did Perl begin supporting this type of structure?
$c = () = $a =~ /\./g
I've come across this several times, and I'm allured by it, it calls to me, but I have to be careful using structures that could trigger warnings or failures in old systems.
I'd actually like to significantly expand my use of this type of structure, so besides this specific example, can anyone point me to the right search terms that describe it, that's multiple assignments of some value generated on the right side of the items? And also I believe various items that could be in the second position, (), though I'm not positive about that. And has this support been consistent since version 5.xxx? Are there various types of this assignment that have been introduced earlier or later?
I have the big Larry Walls Perl book, but I don't know what this is called to begin learning more about it, and what variants will be safe to use.
We have build Perl 5.26.1 from source and used the same Perl to create a perlmodule.c file from an XS file perlmodule.xs.
But when we try to execute this C code, we get the following error.
../perlmodule.c: loadable library and perl binaries are mismatched (got handshake key 0xe280080, needed 0xde00080)
Previously we were using Perl 5.16 and there were no issues. Could you please let us know whether we need to rewrite the XS module for Perl 5.26. Currently we are using the same XS module which is used in Perl 5.16. I am not sure if that is creating the issue here.
We are generating the .c files with following command.
perl ExtUtils/xsubpp -typemap typemap -typemap ExtUtils/typemap perlmodule.xs > perlmodule.cpp
How do I find and replace every letter in a word with a modified version of the word? Basically I need to find any letter [a-zA-Z] and replace it with [aA][zZ].
For Example:
my $word = "layer"
my $new_word = "[l][a][y][e][r]"
Hi Monks,
I want to write the following into and IF clause: "If the number is exactly equal, or equal+1 or equal-1".
I guess I could write it like this:
I have been struggling with the -sticky option with Tk::grid. It does not seem to want to stretch a container for me.
In this simple example I use $gridOrPack to select whether I will grid or pack 2 frames. Then I add a label to one frame and a button to the other frame...
when I set $gridOrPack to 'pack'
I pack with -expand=>1 and fill=>'both', It behaves just like I want... the frames stretch to fill the mainWindow
when I set $gridOrPack to 'grid'
I grid with the -sticky option set to 'nsew' (I've also tried 'ew' and 'ns') and the frames do not stretch.
Am I missing something silly?
use strict;
use Tk;
use Tk::LabFrame;
use Tk::Treeplus;
use Tk::ErrorDialog;
my $mw = MainWindow->new();
my $gridOrPack="grid"; #"pack";
#my $gridOrPack="pack";
my $tpFrame;
my $butFrame;
my $tpFrame=$mw->LabFrame(-label=>'TreePlusFrame');
my $butFrame=$mw->LabFrame(-label=>'ButtonFrame');
if ($gridOrPack=~/grid/i) {
$tpFrame->grid(-row=>1, -column=>1, -sticky=>'ew');
$butFrame->grid(-row=>2, -column=>1, -sticky=>'ew');
}
else {
$tpFrame->pack(-side=>'top',-expand=>1,-fill=>'both');
$butFrame->pack(-side=>'top',-expand=>1, -fill=>'both');
}
$tpFrame->Label(-text=>'I like pack better')->pack(-side=>'top');
$butFrame->Button(
-text => 'Exit',
-command => sub { exit(0) },
)
->pack(qw(-side bottom -pady 10));
MainLoop();
Does perl guarantee that the DESTROY() function will be called immediately after the closing braces} for the objects in the scope created using new() ( as C++ does)?
I have a perl script containing some brief documentation in pod format. Normally (or at least outside of perlpod) $0 is the script name, but in perlpod, $0 is output literally as '$0'.
Is there any way I can dynamically access the current script name inside perlpod? I'm returning to perl after a few years on PHP & can vaguely remember doing something similar in the past.
(I considered submitting this as a meditation, but due to my lack of knowledge on the topic, I thought better of posting there.)
Recently I was thinking about a problem. Specifically, I was considering the idea from the point of view of "ants" (for lack of a better term) following all of the possible paths, and trying to think through how to determine if a path has been completed. As a starting thought experiment, I considered 6 points, with ants moving from each point to each remaining point. I thought of 5 different cases that could occur (points labeled '1'..'6', paths written ordered least to greatest):
Incomplete connection - existing connections are 1-2 and 2-3.
Incomplete connection - existing connections are 1-2, 2-3, 4-5, 5-6, and 1-6
Incomplete connection - existing connections are 1-2, 2-3, 4-5, 5-6, and 1-6, extra connection 4-6
Complete connection - existing connections are 1-2, 2-3, 3-4, 4-5, 5-6, and 1-6
Complete connection - existing connections are 1-2, 2-3, 3-4, 4-5, 5-6, and 1-6, extra connections 3-5, 3-6, and 4-6
(I realized as I was writing this that being able to find that a path might not be as useful as I thought, but that does not take *that much* away from this question.)
I'm not aware of (or at least remember) dealing with graphs in the CS classes I took (years ago), so there may be a nice theory or approach I am not aware of. What I came up with was to create a matrix containing the number of connections between between points. (By writing all of the connections in least-greatest ordering, only half the matrix had to be used, as illustrated by the following. Unfilled entries are noted as '-', otherwise the count of connections is filled in in row-column order.)
What I noticed was that in the cases (1-3) where a connection did not exist, there was at least one row in which the sum of entries on the row was zero, but in cases where a full path existed all rows had a non-zero sum. Is this approach too simplistic-minded (or did I just stumble upon something I should have known)?
Thank you for your attention and insights. (And my apologies if I have wasted your time.)
Update: 2018-07-16
Thank you for your feedback. To answer OM and tobyink, yes, apparently what I am looking for is a Hamiltonian path through the set. (I didn't know the proper term(s) to use to search, among other things.) To answer bliako, yes, I know ants would have started from each point, but for simplicity I showed only completed paths of equal length. To apply this to the original problem, I can see two ways: a) follow the idea of an actual ant, and track each ant's actual position, or b) knowing the edges and their lengths, I would probably look to move down the list of all edges (tracking the sum total) and update the matrix form (above, or other method) to check if a complete path exists.
Hey guys. Consider a function (lets call it A) which returns 1 if a process finished running, otherwise 0. I would like to write another function which should wait until the process will finish running. What's the best why to do it?
I thought of using the while loop and the wait(30); command. Something like this:
I also can just call this subroutine until it will finish, although I don't think its smart because of all unnecessary junk. What's the best way to do so? I'm looking for the cleanest way to do it.
