Question about math.pi is mutable

[Ben Finney]

Bartc <bc at freeuk.com> writes:

> On 07/11/2015 03:43, Ben Finney wrote:
> > Bartc <bc at freeuk.com> writes:
> >
> >> Is there no way then in Python to declare:
> >>
> >>     pi = 3.141519     # etc
> >>
> >> and make it impossible to override?
> >
> > No, and it would be a bad thing if that were something a library author
> > could forbid.
> >
> > Python assumes the programmers using it are consenting adults. Doing
> > harmful things is difficult but not forbidden.
>
> But surely it can't hurt to ensure certain values can't be changed
> accidentally or maliciously?

The value ‘3.141519’ (in your example above) can't be changed. That
value will always be exactly the same, as long as the program is
running.

What I think you mean is “surely it can't hurt to ensure certain names
can never be bound to any value but their initial binding”.

On that I strongly disagree, for the reasons already discussed in this
thread: it arrogates to the library author the power to forbid patching
the library, which cripples extending, debugging, introspection, and a
host of other useful activities.

-- 
 \     “I object to doing things that computers can do.” —Olin Shivers |
  `\                                                                   |
_o__)                                                                  |
Ben Finney