On Thu, Jun 12, 2008 at 8:42 AM, Viktor T. Toth <vttoth at vttoth.com> wrote:
> new_ev(a,b):=apply(ev,[a,b]);
>
> From: Nicola Cabibbo [mailto:nicola.cabibbo at roma1.infn.it]
> Sent: Thursday, June 12, 2008 8:31 AM
> Subject: Re: [Maxima] How to simplify kdelta?
>
> Is there any philosophical reason why..., according to your suggestion, one
> cannot redefine
> ev so that
> new_ev(a,b)= apply(old_ev,[a,b])?
>
apply(ev,...) is an abomination which should never be necessary. Alas, ev,
which started out as a "convenience" routine for the command line -- it is
what is behind the "," syntax as in "x^3,x=3,numer" -- has been overloaded
with a huge variety of tenuously-related functionality, some of it --
notably noun-evaluation -- not available any other way.
As is often the case, what makes for "convenience" in simple interactive
usage makes for semantic obscurity in more complicated cases, whether
programmatic or interactive.
Going forward, we ought to think about how to replace ev(sdf,nouns) and
ev(sdf,noun1,noun2)... with something like ev_nouns(sdf) and
ev_nouns(sdf,[noun1,noun2]), and separate out the (horrible) reevaluation of
variables from the noun-to-verb expansion.
-s