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

Christopher Armstrong radeex at gmail.com
Tue Feb 7 08:19:35 CET 2006

On 2/7/06, "Martin v. Löwis" <martin at v.loewis.de> wrote:

Brett Cannon wrote: > But I know that everyone and their email client is against me on this > one, so I am not going to really try to tear into this. But I do > think that lambda needs a renaming. Speaking as someone who still > forgets that Python's lambda is not the same as those found in > functional languages

Can you elaborate on that point? I feel that Python's lambda is exactly the same as the one in Lisp. Sure, the Lisp lambda supports multiple sequential expressions (the "progn" feature), but I understand that this is just "an extension" (although one that has been around several decades). Of course, Python's expressions are much more limited as Lisp's (where you really can have macros and special forms in as the "expression" in a lambda), but the lambda construct itself seems to be the very same one.

If we phrase it somewhat differently, we can see that lambdas are different in Python and Lisp, in a very practical way. First: Everything in Lisp is an expression. There's no statement, in Lisp, that isn't also an expression. Lambdas in Lisp can contain arbitrary expressions; therefore you can put any language construct inside a lambda. In Python, you cannot put any language construct inside a lambda. Python's and Lisp's lambdas are effectively totally different.

+1 on keeping Lambda, +1 on making it more useful.

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