Yes, the CGI.pm uses tricks to avoid code being compiled by the perl interpreter at script parse time because it is such a big hairy module. Other large modules use similar tricks or tricks with a similar effect. For example, the 'Tk' module.

There is an AutoLoader.pm (in the standard distro) to help you do this kind of thing too if you think it necessary (but be sure you Benchmark first..."premature optimisation is the root of all evil").

One cool thing related to this is what happens when you call a function in an object in perl (using the perl OO syntax).

If I try to call function (or method if you prefer) 'foo()' for an object $bar which is an instance of a 'package Bar;' then perl will look first for a Bar::foo function.

If it doesn't exist (and after chasing up the inheritance heirarchy if the object derives from another) perl will try calling a function called Bar::AUTOLOAD.

This allows you to put in a generic "function not implemented" handler.

For autoloading, you can then pull in the original function but I have also seen (not written :-) code which uses this to implement a bunch of similar functions.

Simply don't implement any of them, but provide an AUTOLOAD method which works out which function was wanted and does the right thing.

In reply to RE: Re: Preloading subs by jbert
in thread Preloading subs by jdavis

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