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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.lang.c
Subject: Re: Recursion, Yo
Date: Sat, 13 Apr 2024 00:10:25 -0000 (UTC)
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On Fri, 12 Apr 2024 15:03:08 +0200, Janis Papanagnou wrote:

> Another one is that you can write (e.g. in Algol 68 or many other higher
> level languages) the equivalent of - again a simple example -
> 
>   int x = 2 * pi * r
> 
> without necessity to know whether pi is a constant, the result of a
> function (calculation), the result of a function implicitly called just
> once on demand, or whatever else. Conceptually as a programming language
> user you want the value.

In Python you can’t do this with an unqualified name, but you can with a 
qualified one, e.g.

    x = 2 * math.pi * r

Which one of these might be true?

* “math” is a module, and “pi” is a variable defined within it
* “math” is a class, and “pi” is a variable defined within it
* “math” is an instance of a class, and “pi” is a variable defined either 
within that instance or the class
* “math” is an instance of a class, and “pi” is a “property”, which is 
computing a value, on demand, via an implicit method call

Note that the fourth possibility does an implicit method call without 
argument parentheses.