Re: [Maxima-discuss] strange problem with autoload

[Stavros M. <mac...@al...>]

For the distinction between evaluation and simplification, see the relevant
manual section <https://maxima.sourceforge.io/docs/manual/maxima_45.html>.

Basically a *routine *(or evaluating function) *does* something, but a
simplifying function *means* something.

Attached please find a simple Lisp file which defines *twenty* as a routine
that returns the number 20, and *thirty *as a simplifying function that
returns 30. Now look at how they behave differently:

load(".../rout-simp.lisp") <<< where ... is the pathname where you put this
file
twenty() => 20
thirty() => 30

So far, they behave similarly. Now let's prevent evaluation by putting them
in quotes *'(...)*:

'(twenty()) => twenty()
'(thirty()) => 30       <<< simplification happened in the absence of
evaluation

And now let's turn off simplification:

simp:false$        <<< This breaks most of Maxima, which depends on
simplification ubiquitously
twenty() => 20   <<< evaluation in the absence of simplification
thirty() => thirty()  <<< no simplification
simp:true$       << restore universe to a sane state

And sure enough, Maxima doesn't autoload simplifying functions (maybe it
should). I'm not quite sure why it works the *second* time with *%solve*,
though....

           -s

On Sun, Sep 4, 2022 at 3:54 PM Oleg Nesterov <ol...@re...> wrote:

> On 09/04, Stavros Macrakis wrote:
> >
> > My guess -- I haven't investigated -- is that this is because %solve is a
> > simplifying function, not a subroutine.
>
> Thanks... please forgive my ignorance, could you explain what does
> "simplifying
> function" mean?
>
> looks like, autoload doesn't work because %solve is the alias. Please see
> the
> trivial test-case:
>
>         $ cat /tmp/test.mac
>         f(x) := x + 1;
>
>         alias(g, f);
>
>         $ maxima -q
>         (%i1) setup_autoload("/tmp/test.mac", g);
>         (%o1)                                done
>         (%i2) g(0);
>         (%o2)                                g(0)
>         (%i3) g(0);
>         (%o3)                                  1
>
> Oleg.
>
>