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Re: Adding linear interpolation to an array

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David Storrs
March 10, 2005 10:37
Re: Adding linear interpolation to an array
Message ID:
> At 17:53 +0100 3/10/05, Thomas Sandlaß wrote:
[request for clarification of 'covariant' and 'contravariant' usage]
> >'Co' means together like in coproduction. And 'contra' is the opposite
> >as in counterproductive. With instanciating parametric types the question
> >arises how a subtype relation between instanciating types propagates
> >to the template. E.g with Int <: Num, covariance would result in
> >Array[Int] <: Array[Num]. Referential classes are actually quite difficult
> >because upon write they are contravariant and covariant when read!
> >So a third case of uncomparable types is needed as well, or it is the default
> >if nothing else is specified.


I appreciate you attempting to explain this, but it remains clear as
mud, at least to me.  Could you please try again, using very short,
very non-technical words and not assuming a mathematical or
scientific background on the part of your reader?

Something that would help: We could all look the words up in a
dictionary, so we don't need a definition.  What we need is a
clarification, in simple terms, of what *you* mean by them, in this

Thank you.


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