Re: Working with constansts

[Ralf Wachinger <rwnewsmampfer@geekmail.de>]

* Barry Margolin wrote:

> In article <mailman.7052.1242121473.31690.help-gnu-emacs@gnu.org>,
>  Nikolaj Schumacher <me@nschum.de> wrote:
> 
>> Richard Riley <rileyrgdev@googlemail.com> wrote:
> 
>>> I don't know enough about Lisp than I can only assume that in this case
>>> it can not be detected at compile time IF you compile to byte/p code.
>> 
>> "Thanks" to dynamic scoping it cannot be caught at compile time.
> 
> It could at least generate a warning.
> 
>> (defconst xxx nil)
>> 
>> (defun change-xxx ()
>>   (setx xxx t)) ;; const or variable?
>> 
>> (let ((xxx nil))
>>   (change-xxx))
> 
> This should also warn about binding a constant.

This recalls the discussions on constants (general), getters and setters
(OOP) in Python to my mind. Functions as wrappers to enforce the
intentions of the programmers. There are no constants (and even no
declarations) in Python, there's only the convention to write intended
constants in capitals. 

For class and instance attributes there are no private, protected or
public declarations (you can even add attributes from outside later) in
Python, there's only a convention to start the intended non-public
attributes with an underline character.

"The pythonic way" informs the users about the intentions, it doesn't
restrict the users. I see that Python and Elisp have a pretty similar
concept on the whole, both are very dynamic and unrestricted.