Re^3: Package Variables

Why didn't perl warn me that I was stepping on a built in package of core significance? Or did perl just include the core "Config.pm" module and mine never actually got loaded?

How would perl know that this is unintentional?

If you write a new program and name it perl.exe, would your OS warn you that ./perl.exe is not C:\Perl\bin\perl.exe?

@INC managment is like @PATH managment, the assumption is you know what you're doing

$ cat Config.pm
package Config; $VERSION=666666; 1;

$ perl -MConfig -le " print $INC{q!Config.pm!}"
C:/perl/5.12.2/lib/MSWin32-x86-multi-thread/Config.pm

$ perl -le "print for @INC"
C:/perl/site/5.12.2/lib/MSWin32-x86-multi-thread
C:/perl/site/5.12.2/lib
C:/perl/5.12.2/lib/MSWin32-x86-multi-thread
C:/perl/5.12.2/lib
.

$ perl -I. -MConfig -le " print $INC{q!Config.pm!}"
Config.pm

$ perl -I. -le "print for @INC"
.
C:/perl/site/5.12.2/lib/MSWin32-x86-multi-thread
C:/perl/site/5.12.2/lib
C:/perl/5.12.2/lib/MSWin32-x86-multi-thread
C:/perl/5.12.2/lib
.
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Comment on Re^3: Package Variables Download Code

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Re^4: Package Variables by kurt2439 (Sexton) on Mar 28, 2011 at 04:12 UTC
I see your point, but still why not warn me? Perl warns me if I declare the same variable name in the same scope even though I may know what I'm doing. It seems like the way the perl warnings pragma operates. It's not like I am doing something hard to predict like overriding some 3rd party CPAN module. This is an expected, core perl module no?	[reply]
Re^5: Package Variables by Anonymous Monk on Mar 28, 2011 at 07:23 UTC
It isn't loading your Config.pm, so how would perl know to warn you? If on the other hand, you knew enough to use lib or -I to get perl to load your Config, you should know enough not to use already used names You could easily write something to warn you, using Module::Find, Module::CoreList, Module::Mapper, Module::Finder, Module::Locate, Devel::Modlist, Module::Which, Module::Which::List, so that `use warnings::modulecollision;` [download] would warn you, but I don't know of any programming language that would try to do that by default, but I don't know of any languages that try to do this at all :) People seem to catch on pretty quick, its like house numbers, you can have many with the same number, as long as the street names are different :)	[reply] [d/l]
Re^6: Package Variables by kurt2439 (Sexton) on Mar 28, 2011 at 12:48 UTC
heh. But if I did try and build a new house with the same number and the same street, I'm pretty sure I would get a "warning" from it's current owner. =o) I'm very grateful for the help -- it's a mistake on my part that I'll be more wary of in the future.	[reply]