it might just be a detail, but Python does not even have single-statement lambdas.  The body of a lambda is an expression yielding a value, not a statement.

Function languages (from which the idea of the Lambda in Python probably came from) do not have statements at all.  Something like the example with "y = x+1; y*2" given earlier is usually expressed as a let-expression, which is syntactic sugar for a lambda itself.  Hence, the example could actually be written in Python like so (I am not saying it is beautiful, but just that it is possible ^_^):
  arr.map( lambda x: (lambda y:y*2)(x+1) )
Or, if you prefer (this seems to me to be syntactically very close to the original):
  arr.map( lambda x: (lambda y=x+1: y*2)() )

Moreover, in Python 3.8, we will have assignments in expressions, and (even though I obviously can't test this) I wonder if you could then write the same thing as:
  arr.map( lambda x: (y := x+1, y*2)[1] )

I guess, the original request is therefore not really about having multi-statement lambdas, but more about extending lambdas to anonymous functions with the possibility to have full statements inside the body.

Finally, I absolutely agree with that good naming is paramount for understandable code.  But IMHO, good naming means that I write a small named function (describing its intent) if its body contains more than just a simple expression, anyway.

Cheers,
Tobias


Quoting Anders Hovmöller <boxed@killingar.net>:

A powerful general purpose language should not limit itself to one statement in a closure.

Nitpick on language: It doesn't. Lambdas are not the only way to do a closure.

It's important to be precise when discussing these things.

Lets add mutli-statement lambdas to python either with just curly braces or with an indent based machine.

Mostly it's just better with a function. Do you have some more compelling examples where you can't use a function smoothly?

/ Anders
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