Padre::Document::Perl:UseriContributed Perl Padre::Document::Perl::Beginner(3)NAMEPadre::Document::Perl::Beginner - naive implementation of some beginner
specific error checking
SYNOPSIS
use Padre::Document::Perl::Beginner;
my $beginner = Padre::Document::Perl::Beginner->new;
if (not $beginner->check($data)) {
warn $beginner->error;
}
DESCRIPTION
This is a naive implementation. It needs to be replaced by one using
PPI.
In Perl 5 there are lots of pitfalls the unaware, especially the
beginner can easily fall in. While some might expect the Perl compiler
itself would catch those it does not (yet ?) do it. So we took the
initiative and added a beginners mode to Padre in which these extra
issues are checked. Some are real problems that would trigger an error
anyway we just make them a special case with a more specific error
message. (e.g. "use warning;" without the trailing s) Others are valid
code that can be useful in the hands of a master but that are poisonous
when written by mistake by someone who does not understand them. (e.g.
"if ($x = /value/) { }" ).
This module provides a method called "check" that can check a Perl
script (provided as parameter as a single string) and recognize
problematic code.
Examples
See <http://padre.perlide.org/ticket/52> and
<http://www.perlmonks.org/?node_id=728569>
Cases
·
split /,/, @data;
Here @data is in scalar context returning the number of elements.
Spotted in this form:
split /,/, @ARGV;
·
use warning;
s is missing at the end.
·
map { $_; } (@items),$extra_item;
is the same as
map { $_; } (@items,$extra_item);
but you usually want
(map { $_; } (@items)),$extra_item;
which means: map all @items and them add $extra_item without
mapping it.
· Warn about Perl-standard package names being reused
package DB;
·
$x = chomp $y;
print chomp $y;
·
map { s/foo/bar/; } (@items);
This returns an array containing true or false values (s/// -
return value).
Use
map { s/foo/bar/; $_; } (@items);
to actually change the array via s///.
·
<@X>
·
if ($x = /bla/) {
}
· Pipe | in open() not at the end or the beginning.
·
open($ph, "| something |");
· Regular expression starting with a quantifier such as
/+.../
·
} else if {
·
} elseif {
·
close;
HOW TO ADD ANOTHER ONE
Please feel free to add as many checks as you like. This is done in
three steps:
Add the test
Add one (or more) tests for this case to t/75-perl-beginner.t
The test should be successful when your supplied sample fails the check
and returns the correct error message. As texts of error messages may
change, try to match a good part which allows identification of the
message but don't match the very exact text.
Tests could use either one-liners written as strings within the test
file or external support files. There are samples for both ways in the
test script.
Add the check
Add the check to the check-sub of this file
(Document/Perl/Beginner.pm). There are plenty samples here. Remember to
add a sample (and maybe short description) what would fail the test.
Run the test script to match your test case(s) to the new check.
Add the configuration option
Go to Config.pm, look for the beginner error checks configuration and
add a new setting for your new check there. It defaults to 1 (run the
check), but a user could turn it off by setting this to 0 within the
Padre configuration file.
COPYRIGHT & LICENSE
Copyright 2008-2011 The Padre development team as listed in Padre.pm.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included
with this module.
perl v5.14.12011-06-18Padre::Document::Perl::Beginner(3)
