[Biococoa-dev] functional groups
Koen van der Drift
kvddrift at earthlink.net
Sat Mar 5 18:56:36 EST 2005
On Mar 5, 2005, at 6:44 PM, Alexander Griekspoor wrote:
> Ideally, say a phosphorylation ADDs something to a symbol, it changes
> it properties, its mass etc but it does STAY for instance a tyrosine.
> That's why I came up with the idea of i.e. symbol features (now this
> is impossible because the symbols are singletons now that I think of
> it) but than perhaps the other way around, we should add
> symbolFeatures (single symbol features) that have additional effects
> than the general features in that they're taken along in
> What I try to say is that I see a problem when you decide to say
> incorporate a phosphorylated-tyrosine instead of a standard tyrosine
> symbol because suddenly part of my BCSequence doesn't respond to
> representedBy: for instance. Or a methylated guanine does not respond
> to complement (which is still something to debate whether to return a
> methylated cytosine then or a non-methylated one but let's leave that
> for a while).
You are absolutely right. What we need is an extension of the BCSymbol
class - without changing its basic properties. So forget about the
BCFunctionalGroup class :) I need to think what would be a proper
solution for this. In Design Patterns lingo it would probably be the
Decorator, see eg
designpatterns.html. I will see how that can be applied to ObjC.
Having fun with the snow ?
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