Proposed PEP for a Conditional Expression

[Michael Chermside]

Markus> What about "(<cond>: return <expr> [else return <expr])"

Skip> All you're saving is a single word and a colon:
Skip> 
Skip>     if <cond>: return <expr>
Skip>     else: return <expr>
Skip> 

No, he's actually proposing a major change to the interpretation of 
"return" in Python -- which is why I don't particularly like this syntax 
(but perhaps this objection can be patched up!).

For instance, consider the following (written using the and-or trick):

     def f(a,b=1):
         x = a > 0  and a or b
         return x ** 2 - 1

Now, if we tried to re-write this in Markus's syntax, we'd get the 
following:

     def f(a,b=1):
         x = a > 0: return a else return b
         return x ** 2 - 1

Apparently Markus's syntax implies that after a colon appearing in a 
statement (as opposed to other, normal :'s in Python), the "return" 
keyword no longer means to return from a function.

Markus... did I mis-interpret? Do you still think this is a useful syntax?

-- Michael Chermside