[Python-3000] Minor hitch writing the Function Signature PEP

[Bill Birch]

On Sun, 23 Apr 2006 05:36 am, Talin wrote:
> @precondition( y=NotNegative )
> def power( x, y ):
>    ...
> ...where 'NotNegative' is a function which simply does an assert( value >= 
0 )
The phrase "y=NotNegative" is a classic type constraint predicate.

Given that type expressions will be dynamic (see GVD blog 
http://www.artima.com/weblogs/viewpost.jsp?thread=87182)  
how about:

def power(x, y : NotNegative):
   body...

or

def power(x, y : not Negative):
   body...

or even:

def power(x, y : (lambda t: t > 0) ):
   body...