Re: [Maxima-discuss] Return a funcion with an if, from block

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

The text below is seriously wrong in almost every possible way:

   - Evaluation happens *before* simplification, not after, recursively.
   For example, given a:3, the processing of a-1 (internally "+"(a,-1) )
   proceeds as follows:
      - evaluate a-1
         - evaluate a, return 3; simplify 3, return 3
         - evaluate -1, return -1; simplify -1, return -1
      - this returns "+"(3,-1)
      - simplify that to get 2
   - What does "try" in "try to evaluate" mean? Although there are parts of
   Maxima which use heuristic methods where multiple approaches are "tried",
   evaluation is strictly algorithmic. There is no "trying".
   - "tells maxima that we want" -- Maxima doesn't care what we want; it
   does what we tell it to do.
   - '() has nothing to do with noun forms.
   - There is no such concept as having a "whole expression in noun form".
   - "Stand here as is" is unintelligible.
   - The '' operator does not "undo" the '() operator.

This (and some similar language that used to be in the Maxima manual) may
explain why so many of our users are confused about '() and ''().

I would recommend *removing this text entirely *until it can be rewritten
by someone who understands Maxima evaluation.

Where exactly does this text appear?

        -s

On Thu, Jul 7, 2022 at 1:26 AM Gunter Königsmann via Maxima-discuss <
max...@li...> wrote:

> The background of my last mail is that I interpreted the maxima manual
> this way and wxMaxima currently states:
>
> Maxima automatically simplifys expressions it gets as input and then tries
> to evaluate their value. The '() operator tells maxima that we want a whole
> expression to be in noun form, which means: stand here as is, and
> unevaluated.
>
> This is useful, for example, if one doesn't want an if() to be executed
> prematurely (which means: Before enough information is available in order
> to decide if the condition is false or true). Another example would be if a
> command checks if its argument contains unassigned variables too early.
>
> The ' operator can be undone by using the '' operator.
>
> => What can we do to improve the documentation of '()?
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