From: Julian Leviston <julian@...>
Date: 2008-04-07T13:01:45+09:00
Subject: Re: Arbitrary mathematical relations, not just hashes

You could use ActiveRecord.

Julian.

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On 07/04/2008, at 9:52 AM, Kelly Jones wrote:

> Many programming languages (including Perl, Ruby, and PHP) support  
> hashes:
>
> $color['apple'] = 'red';
> $color['ruby'] = 'red';
>
> $type['apple'] = 'fruit';
> $type['ruby'] = 'gem';
>
> This quickly lets me find the color or type of a given item.
>
> In this sense, color() and type() are like mathematical functions.
>
> However, I can't easily find all items whose $color is 'red', nor all
> items whose $type is 'fruit'. In other words, color() and type()
> aren't full mathematical relations.
>
> Of course, I could create the inverse function as I go along:
>
> $inverse_color['red'] = ['apple', 'ruby']; # uglyish, assigning list  
> to value
>
> and there are many other ways to do this, but they all seem kludgey.
>
> Is there a clean way to add 'relation' support to Perl, Ruby, or PHP?
>
> Is there a language that handles mathematical relations naturally/ 
> natively?
>
> I realize SQL does all this and more, but that seems like overkill for
> something this simple?
>
> -- 
> We're just a Bunch Of Regular Guys, a collective group that's trying
> to understand and assimilate technology. We feel that resistance to
> new ideas and technology is unwise and ultimately futile.
>