Re: [Maxima-discuss] How do I translate the "ev" in "[a:b,b:c,c:d]; ev('[a,b,c],'a=42); " to a "subst"?

[Eduardo O. <edu...@gm...>]

On Sun, 13 Oct 2024 at 18:24, Stavros Macrakis <mac...@gm...> wrote:

> To elaborate a bit on what Robert said, I strongly discourage you from
> using *ev *programmatically if there is some other way to accomplish what
> you want.
>



Hi all,

I only tried to use ev because the documentation of makelist -
from here:

  (info "(maxima)makelist")
  https://maxima.sourceforge.io/docs/manual/maxima_21.html#makelist

says this:

  The most general form, 'makelist (<expr>, <i>, <i_0>, <i_max>,
  <step>)', returns the list of elements obtained when 'ev (<expr>,
  <i>=<j>)' is applied to the elements <j> of the sequence: <i_0>,
  <i_0> + <step>, <i_0> + 2*<step>, ..., with <|j|> less than or
  equal to <|i_max|>.

and that gave me the impression that it was standard, or at least
common, to use ev to explain the semantics of special forms... but I
find ev very confusing - and I only tried to understand ev because
I tried this,

  [a:'b, b:'c, c:'d];                /* [b,c,d] */
  ['a, a, ''a, ''''a];               /* [a,b,c,d] */
  makelist([a,b,c],    'a, 42,43);   /* [[42,c,d], [43,c,d]] */
  makelist([a,b,c],     a, 42,43);   /* [[42,c,d], [43,c,d]] */
  makelist([a,b,c],   ''a, 42,43);   /* [[b,42,d], [b,43,d]] */
  makelist([a,b,c], ''''a, 42,43);   /* [[b,c,42], [b,c,43]] */

and I found the result of the first makelist very surprising.

Anyway: now I have many more things in my to-do list... I need to
finish some experiments with Sly/Slime (urgent), understand the last
messages by Robert and Stavros (urgent), and learn how to use trace
(not urgent). =/

  Cheers, thanks, etc...
    Eduardo