Question:Why can't `use` be used as or within an expression?

Question:Why can't `use` be used as or within an expression?

Maple 2023

This question is an expansion of my previous reply.

There exist sixty kinds of statements in Maple, whose major pro​​​​portion can be used as an expression or within an expression (e.g., assignment, loop, and condition). But why is `use` an exception?

Moreover, since it is reasonable to think of `use` as a (partial) generalization (see below) of the `subs` function, shouldn't the behaviour of `use` be consistent with `do`/`if`?

Compare: "seq((…;…;…), x in x__0):" (not allowed) vs. "for x in x__0 do …;…;… od:" (allowed); "subs(x = x__0, (…;…;…)):" (not allowed) vs. "use x = x__0 in …;…;… od:" (Not allowed! Why?).)

Edit. Besides that, is there some workaround to do something like

```  # If `use` can be used as an expression or within an expression,
use x = 2 + y in 'use y = 4 in x + y end' end;
# should return “use y~ = 4 in (2 + y) + y~ end use;” and
(use y = 2 + x in x -> x + y end);
# should output “x~ -> x~ + (2 + x);”.
# Unfortunately, I cannot find a workaround to stimulate them.```

at present? Note that the `subs` function is unable to do so, so in my opinion, only when the use of `use` is no longer limited to statements will it become a sweeping generalization of `subs`.

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