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

[Cliff Wells]

On Fri, 2008-09-12 at 00:10 +0200, Mathias Panzenböck wrote:
> The only thing I'd like would be anonymous classes (like in java) and anonymous
> functions:

> I don't think anything else concerning statement as expression is in any way
> necessary or handy.

At one time I also perceived a shortcoming in lambda.  You could
continue to see it this way, or you could see it (like I now do) that
it's not lambda that's limited (it effectively allows an arbitrary
number of expressions), but rather the fact that a statement cannot be
be used as an expression.

For instance, the following is currently legal in Python:

lambda x, y: (
    x + y,
    x**2,
    y**2
)

But this is not:

lambda x, y: (
    if x > y: x     
    else: y
)

Whether or not it's illegal is due to lambda being limited or because
statements are castrated expressions is all a matter of your point of
view.  Extending lambda to allow statements would certainly fix
*lambda*, but making statements into expressions fixes Python (IMHO, of
course).

Regards,
Cliff