[Python-ideas] Statements vs Expressions... why?

[Greg Ewing]

Cliff Wells wrote:

> factors = for x in range ( 2, n ):
>     if n % x == 0:
>         yield x

Is this construct meant to be a list comprehension or
a generator expression? If it's a GC, you just get
factors bound to an iterator, not a list of results
from that iterator. If it's an LC, then what do you
do if you want a dict or tuple comprehension instead?

Also, 'yield' already has a meaning that's different
from what you seem to want here. Consider:

   def foo(n):
     for x in range ( 2, n ):
       if n % x == 0:
         yield x

Here the whole function is a generator, and the yield
causes an item to be returned to the generator's caller.
Now, if there is no difference between a statement and
an expression, the following should do exactly the
same thing:

   def foo(n):
     factor = for x in range ( 2, n ):
       if n % x == 0:
         yield x

-- 
Greg