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Re: initial impressions/questions

This page is part of the web mail archives of SRFI 39 from before July 7th, 2015. The new archives for SRFI 39 contain all messages, not just those from before July 7th, 2015.

At Sun, 22 Dec 2002 22:27:45 -0500, Marc Feeley wrote:
> > I find this line of reasoning so compelling that I now advocate the
> > elimination of `make-mutable-parameter'.
> You mean: parameters should be mutable according to the specified
> semantics and "make-parameter" should create mutable parameter
> objects, consequently "make-mutable-parameter" can be removed.

No, I meant simply that `make-mutable-parameter' should be removed,
with `make-parameter' left alone.

So there would be no mutable parameters, because programmers can easily
get them through mutable objects that are stored as parameter values.

> > FWIW, I found your arguments in favor of `make-mutable-parameter'
> > uncompelling: no particular use for it, but seems on the surface to be
> > easier to implement, etc. These sort of arguments seem suspiciously
> > like the ones that support dynamic scope over lexical scope.
> No the "efficiency of implementation" (of thread creation and
> continuation transfer) is only a secondary reason.  The primary reason
> is that the semantics of parameter objects is closer to lexical
> variables (the only difference is dynamic vs. lexical scope).  This
> makes them easier to understand. 

These are still unsatisfyingly abstract answers to me. I really want to
see how one choice or the other makes programming easier, and I guess
I'll have to keep looking for examples. Meanwhile, if mutable
parameters must stay, I yield.