At 07:00 03.12.2003 -0800, Guido van Rossum wrote:

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The old lambda would have to be kept around for a while for programs relying on the old semantics, but it could be deprecated, and removed in 3.0.

I'm not sure that the -> notation is more understandable than lambda; it would surely confuse C/C++ programmers who are new to Python.

Scary thought: how about simply introducing early-binding semantics for lambda in 3.0?

that would confuse schemers <wink>

Another radical idea would be to use an anonymous-block notation like Smalltalk and Ruby. We could use some kind of funky brackets like [|...|]. A lambda would require an argument notation too. I believe Ruby uses [|x| x+1] where we would write lambda x: x+1, maybe we could use [|x: x+1|]. (I like structure with an explicit close more than open ones like lambda.)

I would expect blocks to be blocks, accepting also statements and sharing the scope with the surrounding code, not having early-binding semantics. Honestly, given the introduction of generator exprs, a substitute expression for lambda with early-binding semantics makes sense. Personally I can see it also as meaningful wrt the statemenent/expression dichotomy in python, and we would have early-binding as a general rule for "expressions". But again I think that a block-like syntax should be used, if at all, for real blocks. regards.