Re: Using a module more than once

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Re^2: Using a module more than once by kwaping (Priest) on Aug 02, 2005 at 15:22 UTC
I guess I could do that - thanks for the suggestion! I just wanted to load them situationally, as not all of them are needed for every method. Or am I misunderstanding how that mechanism works?	[reply]
Re^3: Using a module more than once by bart (Canon) on Aug 02, 2005 at 15:54 UTC
Or am I misunderstanding how that mechanism works? You are. Any module that gets used, will be loaded at compile time, thus, when your module is loaded. So there's no use in putting a use statement inside a method. Sometimes, when some modules are only needed in exceptional circumstances, people can use a require statement in a method or sub, for example to load Carp in an error trapping routine. You have to be aware of the differences between use and require: require doesn't call import in the loaded modules, and it won't change the allowable syntax for your code either. Thus, subs defined in that module won't be easily recognized as such in the loading script. It's something to look out for. For OO modules, it makes no difference, whether you choose use or require.	[reply]
Re^4: Using a module more than once by techra (Pilgrim) on Aug 02, 2005 at 17:04 UTC
However, as I understand it, you can delay use calls if you are using SelfLoader and then execute the use call inside of a subroutine. Example: `use SelfLoader; sub __PACKAGE__::myfunc; 1; __DATA__ sub myfunc { use ThisOtherModule; }` [download]	[reply] [d/l]
Re^5: Using a module more than once by bart (Canon) on Aug 02, 2005 at 17:11 UTC
Re^6: Using a module more than once by techra (Pilgrim) on Aug 02, 2005 at 17:27 UTC
Re^3: Using a module more than once by davidrw (Prior) on Aug 02, 2005 at 15:33 UTC
yes -- `use` causes everything to be loaded at the beginning.. if you want it conditionaly loaded, one way is to do `require Foo::Bar` instead. (Also see my other reply below) Update: See Also: use vs. require use vs require use vs. require in LWP::Simple use vs. require in string eval?	[reply] [d/l] [select]
Re^4: Using a module more than once by kwaping (Priest) on Aug 02, 2005 at 15:36 UTC
Great, thanks for the clarification! I'll switch to one of those other styles (either doing all the "use" statements at the head of the file, or using require instead).	[reply]
Re^3: Using a module more than once by holli (Abbot) on Aug 02, 2005 at 15:35 UTC
You're misunderstanding. `use` happens at compile time. Consider: `#file: /perl/site/lib/Foo.pm package Foo; use strict; use warnings; sub bar { return "BAR"; } 1; #file: test.pl use strict; use warnings; my $i = 0; if ( $i ) { use Foo; } print Foo::bar; #prints "BAR"` [download] holli, /regexed monk/	[reply] [d/l] [select]