RE: Operators '=' ‘:=’ ‘::=’ in manual

[DUDZIAK Krzysztof]

Variables defined using '=' are, according to manual' expanded recursively
and they do allow self-referencing. However if one uses latter one, they
land onto infinite recursion (as you mentioned). These are two separate 
questions
* to be allowed
* to result in some special effect

> -----Original Message-----
> From: Paul Smith [mailto:psmith@gnu.org]
> Sent: Freitag, 11. Dezember 2020 19:04
> To: DUDZIAK Krzysztof <krzysztof.dudziak@thalesgroup.com>; bug-
> make@gnu.org
> Subject: Re: Operators '=' ‘:=’ ‘::=’ in manual
> 
> On Thu, 2020-12-10 at 18:40 +0000, DUDZIAK Krzysztof wrote:
> > I don't actually dare to use terms "recursive variable" and "simple
> > variable" as myself didn't find such in manual. Terms which I found
> > read variable expanded recursively variable expanded simply
> 
> I still believe these are poor terms.
> 
> All variables are "recursively expanded" when they are expanded: that is, all
> references to all variables inside the value are expanded, and all references
> to all variables inside any of those values are expanded, etc. recursively.
> Expansion happens identically in all cases.
> 
> The difference is not in HOW they are expanded, but rather WHEN they are
> expanded.
> 
> The term probably was used to refer to one specific difference which is that
> recursively expanded variables don't allow you to have self- referencing; you
> can't do this:
> 
>     FOO = bar $(FOO)
> 
> because you'd get "infinite recursion".  That is certainly one legitimate
> difference but I don't think it deserves to drive the naming .  But as I say,
> these terms have been in the docs since forever so changing them would
> need to be done carefully.