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IWETHEY Home / IWETHEY Board / Theory and Practice of Programming Forum / Along similar lines...
Post #83,351
by ChrisR
2/22/03 12:44:30 AM
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New Along similar lines...
Polymorphic dispatch from an OOP perspective also solves the problem. Instead of building the logic for the code in the user, build a common interface for the objects and have the object itself define what happens in the specific situation.

And, yes, Control Tables as a method of dispatch will go unmentioned. :-)
Post #84,143
by tablizer
2/25/03 9:11:49 PM
Reply
New Multimorphism
Polymorphic dispatch from an OOP perspective also solves the problem. Instead of building the logic for the code in the user, build a common interface for the objects and have the object itself define what happens in the specific situation.

Only in "clean" shape, animal, device-driver, and stack examples. The real world often dispatches on multiple orthogonal criteria such that OO polymorphism cannot handle it nicely because polymorphism is mostly mono-dispatch.

Nor is it always convenient to make a seperate class for every combination of multiple orthogonal dispatching factors in order to partition them. At least case statements can be turned into IF statements when things get complex without having to do the Class Shuffle. Thus, case statements are more change-resistent.

And, yes, Control Tables as a method of dispatch will go unmentioned

Generally not a strong candidate unless the case list gets long and/or is duplicated in multiple spots.
________________
oop.ismad.com
     Programming algorithms, switch() and Perl. - (static) - (25) - Feb. 21, 2003, 12:42:42 AM EST
         well its not perl - (boxley) - (1) - Feb. 21, 2003, 09:02:32 AM EST
             That's a point. - (static) - Feb. 22, 2003, 05:04:33 AM EST
         What's the diff? If it needs a "break", it's just as stupid! -NT - (CRConrad) - (13) - Feb. 21, 2003, 10:22:36 AM EST
             The difference is ... - (drewk) - (1) - Feb. 21, 2003, 10:40:14 AM EST
                 Right, slight assembler efficiency gain. -NT - (admin) - Feb. 21, 2003, 10:49:24 AM EST
             Re: What's the diff? - (admin) - (10) - Feb. 21, 2003, 10:47:57 AM EST
                 Couple more - (tuberculosis) - Feb. 21, 2003, 03:45:11 PM EST
                 It's a kind of concealed goto. - (static) - Feb. 22, 2003, 05:03:45 AM EST
                 Scott's closest, but not even he got it - my fault, though: - (CRConrad) - Feb. 23, 2003, 05:52:26 PM EST
                 VB does some things right - (tablizer) - (6) - Feb. 25, 2003, 08:59:17 PM EST
                     If I'm not mistaken... - (ChrisR) - (1) - Feb. 25, 2003, 11:13:58 PM EST
                         poor substitute for Boolean expressions - (tablizer) - Feb. 26, 2003, 03:00:17 PM EST
                     Well, close. But cooler is the range stuff - (tseliot) - (3) - Feb. 26, 2003, 02:03:07 AM EST
                         Fugly syntax kind'a repeats itself: YTF "select" AND "case"? - (CRConrad) - (2) - Feb. 26, 2003, 06:34:26 AM EST
                             Not trying to imply invention - (tseliot) - Feb. 26, 2003, 11:44:38 AM EST
                             Pascal was invented before Visual BASIC - (orion) - Feb. 26, 2003, 08:09:43 PM EST
         One more thing: - (jb4) - (2) - Feb. 21, 2003, 02:17:54 PM EST
             Constant vs an expression - (ben_tilly) - (1) - Feb. 22, 2003, 02:55:32 PM EST
                 That's sorta what I figger... -NT - (jb4) - Feb. 27, 2003, 09:16:11 AM EST
         Comments and thoughts... - (Simon_Jester) - (5) - Feb. 22, 2003, 12:33:27 AM EST
             Along similar lines... - (ChrisR) - (1) - Feb. 22, 2003, 12:44:30 AM EST
                 Multimorphism - (tablizer) - Feb. 25, 2003, 09:11:49 PM EST
             Sometimes that's overkill. - (static) - Feb. 22, 2003, 05:11:36 AM EST
             $foo->{$key} - (admin) - Feb. 22, 2003, 07:05:49 AM EST
             You are probably thinking of - (ben_tilly) - Feb. 22, 2003, 02:54:15 PM EST

But at least you can make it swallow the code.
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