unintuitive for-loop behavior

[Grant Edwards]

On 2016-09-30, Steve D'Aprano <steve+python at pearwood.info> wrote:

> To me, "make for-loops be their own scope" sounds like a joke feature out of
> joke languages like INTERCAL. I'm not aware of any sensible language that
> does anything like this.

In C99 a for loop has its own namespac:

  int main(void)
  {
    for (int i=0; i<5; ++i)
      printf("i=%d\n",i);
  }

If you try to access 'i' outside the for loop, it's an error, because
it doesn't exist in the file, global or 'main' namespace.  It only
exists in the for-loop's namespace.

I think that's an absolutely brilliant feature, and I use it a _lot_
when writing C code.  I'm a big fan of minimizing the lifetime/scope
of variables. I wish if/then/else did the same thing:

  if ((r=some_function()) != R_SUCCESS)
    printf("some_function() failed with status %d\n",r);

-- 
Grant Edwards               grant.b.edwards        Yow! I don't know WHY I
                                  at               said that ... I think it
                              gmail.com            came from the FILLINGS in
                                                   my rear molars ...