On Mon, Oct 06, 2003 at 01:33:18PM +0200, Nicolas Cannasse wrote:
> > > Yikes. The good thing about the previous code was it _wasn't_ purely
> > > functional.
> > >
> > > I'll never understand this fear of mutability.
> >
> > I have no fear of mutability. It's just that there was absolutely
> > no apparent advantage of having mutability in this datastructure,
> > neither performance- nor expressiveness-wise. A reference holding this
> > datastructure outside of the library would do as well. You are not afraid
> > of dereferencing values, are you? ;-)
>
> Manipulating references is most of the time quite a pain, and make the code
> quite ugly.
> I understand in some cases the need of pure functional data structure (Coq
> code proof) but in the "average user" cases that target ExtLib, having a
> mutable structure is surely better. For example I often use an Hashtable
> where a Map would be better for theses two reasons :
> - no need to define a module type (this is corrected by this polymorphic
> version)
> - the hashtable is mutable ! means, easy to use.
FWIW implementing mutable map on top of non-mutable one is easier and
more efficient then vice versa. Just need to use ref. Otherwise you need
to do some copy() tricks.
--
: Michal Moskal :: http://www.kernel.pl/~malekith : GCS {C,UL}++++$ a? !tv
: When in doubt, use brute force. -- Ken Thompson : {E-,w}-- {b++,e}>+++ h
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