RE: (3) (tilly) 1: Fly Subroutines on the Fly

That's only easier to maintain if your subroutines are as simple as just doing division. But mine arn't, they are actually about a dozen or so lines of code, and only have a few points of optimization. It would be silly to have an IFTE structure returning one of 6 or 7 different possabilities... I would have to apply a simple change to every possability rather then one string. That becomes a maintanance nightmare. Hence the question in the first place... what is the best way to assemble an anonymous subroutine on the fly. (I am also curious how CGI.pm does it, since those subroutines are actually named!)

Tilly gave an answer as to why my eval was failing, but he then went on to confuse me with his disapproval of my method followed by a description of what I should do (which was exactly what I thought I WAS doing). I am somewhat confused by that, and perhaps someone can enlighten me.

Comment on RE: (3) (tilly) 1: Fly Subroutines on the Fly

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Apologies for the confusion. by tilly (Archbishop) on Sep 19, 2000 at 19:49 UTC
What I didn't think was worthwhile is worrying about which low-level operation you can get away with which times. Instead analyze your code for steps that may or may not ever be needed, and only include the ones that you are using this time. This results in a structure with a lot of single level if statements, which avoids the explosion of possible combinations. Flexibility without undue code complication and without paying run-time performance except for the steps you need. As for what CGI does, the trick is that if you have a function in a package named AUTOLOAD, then it will be called on any unknown functions or method calls. $AUTOLOAD is the name of the unknown method. So what happens is that he creates a hash of possible methods he may or may not ever need, and an AUTOLOAD function. Upon your first trying to call a function or method he creates it on the fly and runs it. Upon your second try the method is already there, and is called directly. If you need all of the methods this is slower than just compiling directly. If you only need a few then this is faster.	[reply]

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Apologies for the confusion.
by tilly (Archbishop) on Sep 19, 2000 at 19:49 UTC

This results in a structure with a lot of single level if statements, which avoids the explosion of possible combinations. Flexibility without undue code complication and without paying run-time performance except for the steps you need.

As for what CGI does, the trick is that if you have a function in a package named AUTOLOAD, then it will be called on any unknown functions or method calls. $AUTOLOAD is the name of the unknown method. So what happens is that he creates a hash of possible methods he may or may not ever need, and an AUTOLOAD function. Upon your first trying to call a function or method he creates it on the fly and runs it. Upon your second try the method is already there, and is called directly. If you need all of the methods this is slower than just compiling directly. If you only need a few then this is faster.

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