[Python-Dev] removing nested tuple function parameters (original) (raw)

Raymond Hettinger raymond.hettinger at verizon.net
Mon Sep 19 02:10:20 CEST 2005

[Brett]

Is anyone truly attached to nested tuple function parameters; ``def fxn((a,b)): print a,b``?

I am.

ditching them thanks to the pain they caused in the AST branch.

Changing the grammar for the convenience of a particular AST implementation carries zero weight with me -- that is the tail wagging the dog.

Besides, I had thought that one of the goals of AST was to make it easier to experiment with language. Are you finding that it has a hard time even with the existing grammar? AFAICT, nested tuple arguments presented no problem for Jython or PyPy.

Plus I don't think they are used very much (gut feeling, though, and not based on any grepping).

python-dev grammar change proposals should probably be held to a higher standard than "gut feeling, just toss it" whims.

[Nick]

The fixes needed to make them work properly didn't seem all that ugly to me.

That pretty much settles it the "do it for the convenience of AST" argument.

[Andrew Bennetts]

Please keep them! Twisted code uses them in places for Deferred callbacks that need to deal with multiple return values.

And that settles the question of whether people are using them in real code.

Raymond

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