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

Blake Winton bwinton at latte.ca
Wed Sep 10 21:47:19 CEST 2008

Cliff Wells wrote:
> I'd like to see things like "if" statements, "for" loops,
> etc, become expressions.
> Any thoughts on this?  I'm sure it's been brought up before, but I
> haven't found any definitive discussions on why this rather arbitrary
> design decision continues to hold in the face of a general migration
> away from imperative languages (especially when it seems it could be
> changed without much backwards-compatibility issues).

Can you show me what an "if" in a "lambda" used in a function call would 
look like?  My major complaint with the statements-as-expressions is 
that multi-line statements really don't look good when used in 
expression contexts.  Perhaps you have a good suggestion for the syntax, 
and if so, I'ld love to see it.

 > I've not delved into the internals of the Python interpreter to check,
 > but I suspect that converting most statements to expressions would not
 > be very difficult (changing the grammar definition and generated
 > bytecode a small amount in most cases).

Well, I suspect that delving into the internals to check this theory 
would make people take your proposal a lot more seriously.  Heck, I'ld 
go so far as to say that without doing that, it's all just talk, and 
talk is cheap.  ;)


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