Re: How to keep a script from bombing due to a missing module?

With eval and require you can check if a certain module is available or not. If it is, you can use it, if it isn't, you may decide on going an alternative path at runtime, like this:

eval { require SomeModule; };

if($@) {
    print "SomeModule not found, doing something else\n";
} else {
    SomeModule->do_something;
}
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Re: Re: How to keep a script from bombing due to a missing module? by eyepopslikeamosquito (Archbishop) on May 22, 2004 at 10:05 UTC
Good advice. Further, note that: `use SomeModule ();` [download] is equivalent to: `require SomeModule;` [download] while: `use SomeModule;` [download] is equivalent to: `require SomeModule; SomeModule->import();` [download] with the use done at compile time and the require done at run time. See perlmod for more details. For this to work smoothly with require, be sure to always call user-defined subroutines in SomeModule with parens, to allow the Perl parser at compile time to recognize subroutine calls in a module that has not been loaded yet. See also: Re: New Discovery!!! (sub call without parentheses) - Coding Style and Re: How to create symlink using Perl? (Unix symlinks vs Windows Junctions).	[reply] [d/l] [select]

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Re: Re: How to keep a script from bombing due to a missing module?
by eyepopslikeamosquito (Archbishop) on May 22, 2004 at 10:05 UTC

Good advice. Further, note that:

use SomeModule ();
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is equivalent to:

require SomeModule;
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while:

use SomeModule;
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is equivalent to:

require SomeModule;
SomeModule->import();
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with the use done at compile time and the require done at run time. See perlmod for more details.

For this to work smoothly with require, be sure to always call user-defined subroutines in SomeModule with parens, to allow the Perl parser at compile time to recognize subroutine calls in a module that has not been loaded yet.

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