how to write function that returns function

[Kragen Sitaker]

spam at bugbear.com (Paul Graham) writes:
> It looks as if the closest thing would be something like this,
> which a Python expert sent me:
> 
> def foo(n):
>   s = [n]
>   def bar(i):
>     s[0] += i
>     return s[0]
>   return bar

I don't think it's accurate to refer to me as a "Python expert".
Maybe someone else sent you essentially the same thing?

> Incidentally, here is Perl 5 code someone sent me for this case:
> 
> sub foo {
>   my ($n) = @_;
>   return sub {return $n += $_[0]}}

The final } should be on the next line for normal Perl style, and the
second 'return' is gratuitous.  (Neither 'return' is necessary, but
only the second one is bad style.)