[Python-Dev] Let's just keep lambda (original) (raw)

Michael Urman murman at gmail.com
Tue Feb 7 16:47:46 CET 2006

On 2/6/06, Brett Cannon <brett at python.org> wrote:

And I think that a deferred object would help with one of lambda's biggest uses and made its loss totally reasonable.

The ambiguity inherent from the perspective of a deferred object makes a general one impractical. Both map(Deferred().attribute, seq) and map(Deferred().method(arg), seq) look the same - how does the object know that the first case it should return the attribute of the first element of seq when called, but in the second it should wait for the next call when it will call method(arg) on the first element of seq?

Since there's also no way to spell "lambda y: foo(x, y, z)" on a simple deferred object, it's strictly less powerful. If the current Python lambda's functionality is desired, there is no better pythonic way to spell it. There are plenty of new syntactic options that help highlight its expression nature, but are they worth the change?

MIchael

Michael Urman http://www.tortall.net/mu/blog/

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