Accessing variable from a function within a function

[James Stroud]

Nathan Harmston wrote:
> Hi,
> 
> I m playing around with extended euclids algorithm from Knuth. I m
> trying to build a function with a function inside it.
> 
> def exteuclid(m,n):
>  a,a1,b,b1,c,d = 0,1,1,0,m,n
>  def euclid(c,d):
>        q = c /d
>        r = c % d
>        if r == 0:
>            print a,b
>            return d
>        else:
>            print a1,a,b1,b,c,d,q,r
>            t = b1
>            b = t - q * b
>            a = t - q * a
>            c,d,a1,b1 = d,r,a,b
>            return euclid(c,d)
>    return euclid(c,d)
> 
> Unfortunately this doesnt work since a,a1,b,b1 arent declared in the
> function. Is there a way to make these variables accessible to the
> euclid function. Or is there a better way to design this function?
> 
> Many Thanks in advance,
> 
> Nathan

That last return statement does not match indentation of another block. 
But this is probably what you mean:

def exteuclid(m,n):
  x = 0,1,1,0,m,n
  def euclid(c,d,x=x):
        a,a1,b,b1,c,d = x
        q = c /d
        r = c % d
        if r == 0:
            print a,b
            return d
        else:
            print a1,a,b1,b,c,d,q,r
            t = b1
            b = t - q * b
            a = t - q * a
            c,d,a1,b1 = d,r,a,b
            return euclid(c,d)
        return euclid(c,d)

James