Let-expressions

[sloisel]

Dear All,

I searched this group and found that there have been discussions about
introducing a let expression to the language so that you can define
local variables in a lambda. I.e., something like f=lambda x: let
y=x^2 in sin(y). (My syntax is unpythonic, but I hope you get it).

Can someone tell me what eventually happened?

Thanks,

Seb

 

[Terry Reedy]

Dear All,

I searched this group and found that there have been discussions about
introducing a let expression to the language so that you can define
local variables in a lambda. I.e., something like f=lambda x: let
y=x^2 in sin(y). (My syntax is unpythonic, but I hope you get it).

Can someone tell me what eventually happened?

The discussions ended.
Proposals for assignment expressions have been rejected.

 

[Chris Rebert]

The discussions ended.
Proposals for assignment expressions have been rejected.

To elaborate slightly, if you need anything more complicated than a
single expression, then *don't use a lambda*. Just use a named
function. It's much clearer and easier.
Proposals to extend lambda usually spiral/evolve into wanting to make
lambda multi-line, which has repeatedly been found to be incompatible
with Python's indentation-based syntax; and, again, you can just use a
named function.

Cheers,
Chris

 

[sloisel]

Thanks for the quick replies.

I didn't want statements in my expressions, just let-expressions.
That's okay, it was just a question.

Sébastien Loisel