[Python-Dev] Lockstep iteration - eureka! (original) (raw)

Greg Ewing greg@cosc.canterbury.ac.nz
Thu, 10 Aug 2000 14:12:08 +1200 (NZST)

Thomas Wouters <thomas@xs4all.net>:

The only objection I can bring up is that parentheses are almost always optional, in Python, and this kind of violates it.

They're optional around tuple constructors, but this is not a tuple constructor.

The parentheses around function arguments aren't optional either, and nobody complains about that.

'for (x in a, y in b) in z:' is valid syntax...

But it's not valid Python:

for (x in a, y in b) in z: ... print x,y ... SyntaxError: can't assign to operator

It might not be too pretty, but it can be worked around ;)

It wouldn't be any uglier than what's currently done with the LHS of an assignment, which is parsed as a general expression and treated specially later on.

There's-more-to-the-Python-syntax-than-what-it-says-in- the-Grammar-file-ly,

Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg@cosc.canterbury.ac.nz +--------------------------------------+