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From: "Pascal J. Bourguignon" <pjb@informatimago.com>
Newsgroups: comp.programming
Subject: Re: Best practice for using constants outside of code?
Date: Wed, 02 Feb 2011 21:29:42 +0100
Organization: Informatimago
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Ikke <ikke@hier.be> writes:

> <snip>
>> That can only be solved by adding another layer of constant/value 
>> definitions.
>> How about a simple .INI file?
>
> Thanks for your suggestion!
>
> Unless I incorrectly interpreted your suggestion, that would leave the same 
> problem I guess...
>
> The original ini file would be changed from:
> person.gender=1
> to:
> person.gender=ConstGenderMale
>
> The ini file holding the constants would define the constants as:
> ConstGenderMale=1
>
> And the constants in code would remain the same:
> ConstGenderMale=1
>
> As soon as anybody makes a change in either code or .ini, he/she will need 
> to remember to change the counterpart in .ini or code as well, which is 
> what I was trying to avoid.

Obviously, you will have to define your constants differently:

const
   ConstGenderMale = "ConstGenderMale";
   ConstGenderFemale = "ConstGenderFemale";


Then of course, since you will have to provide functions to read and
write these representations and convert them into these constant values,
you might want to define a class:

class: Symbol
   slots:
       name: String;
       value: String;

function keyword(name)
   new Symbol name=name value=name

function read:
   token := parseToken();
   if token.type = identifier then
      return keyword(identifier)
   else
      ...

method print (self Symbol)
   write(self.value)



So you can define:

const
  ConstGenderMale   = keyword("ConstGenderMale");
  ConstGenderFemale = keyword("ConstGenderFemale");



Of course instead of apply Greenspun's Tenth Law all the time, you could
also just use Lisp.
  
-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.