Re: Re: Function memoization

> >     Florent> one).  I think such a "sequence identity" doesn't exist
> >     Florent> in the CRs.
> 
> > Re-formulate that as compare each item of the sequence of identity as
> > determined above.
> 
>   Yes, you are right.  I did hesitate between the two possibilities. 
> The later has the advantage to can be defined in terms of standard
> operators ('eq' and 'is').

If in the context of memoisation we accept that "identity" is equivalent
to all-memberwise identity of the items of the two sequences, then the
effect of memoising long sequences arguments will be negative! It will
actually be harmful!

I am proposing to leave developers the potential to define and implement
sequence "identity" in the context of memoisation using other definitions
(such as the reasonable comparison of a single "sequence-reference").

Also, developers could have a flexible definition, so that memberwise
comparison could be used for sequences up to, let's say, ten items and
reference (ID) comparison will be used for comparing longer sequences.
This treshold can even be determined dynamically depending on the speed of
execution.

This is the way to achieve maximum effect of memoisation without the harm
(that would result for long sequence arguments) of imposing strict
memberwise comparison.

Think of developers as often clever people that are capable of making the
right decision in a particular situation.


Cheers,
Dimitre Novatchev

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