[randomguy1254]

Sorry, I edited my comment and you may have missed it. How would you emulate multi-line closures in Python? A free function which you can pass to a higher order function is not a closure. I think you would need to create a functor, and that becomes even more verbose.

[Chris2048]

What do you mean by closure in this case?

[randomguy1254]

Closures are functions that can capture values/references visible in the scope where the function is defined/instantiated. They are basically a short hand way of creating function objects, functions which have data members.

[Chris2048]

I believe all functions are object in python, so you can add attributes to them, but you'd be better of creating a class with a __call__ method. Relevant scope can be captured in the class __init__.

Classes themselves can hold multiple functions/methods, and if you want a function that carries state, maybe a generator would be useful?

[randomguy1254]

I think this is the point. You can do all these things, but they are all extra hoops you have to jump through when all you want/need is an anonymous on-the-spot closure.

[Chris2048]

I'll grant you that a class isn't an anonymous function, arguably it's the same with lambdas that aren't as powerful as proper function defs.

But I'm not sure this is a problem. In fact, in some ways it may be advantageous e.g. static analysis.

I'd need a use-case for the anonymous closure, but a generator is a basic concept in python, so I son't think it's any trickier than a js function.

I know how in js there is a degree of 'binding' scope and hiding functionality in closures - I think in python (for better or worse) things would by convention be implemented differently.

As an aside, would you say js scope/closure approach is a bit similar to the approach in R?

[randomguy1254]

"lambdas that aren't as powerful as proper function defs" I don't really follow this. I think we should use the right tool for the job. I don't need something that is "more powerful" but comes with extra verbosity and requires me to jump around the source code if I'm not using the extra power.

"In fact, in some ways it may be advantageous e.g. static analysis." Curious why static analysis can't handle closures? Also, I want to use expressive constructs as a programmer, not be arbitrarily limited by what some static analyzer can handle. There may be cases where you are tied to a certain language and analyzer, but in the general case, I don't follow this argument.

"I'd need a use-case for the anonymous closure." I don't want to delve too much into the usefulness of closures, but they definitely exist for a reason. They are useful as parameters to metafunctions for example, which are used extensively in certain programming styles (ie, more functional styles). Closures are basically syntactic sugar. You don't need them, but they can really make things cleaner/simpler in some cases, and are natural constructs to use in certain paradigms. They can also be used in factory functions as a more succinct way to create an object (point might be lost if you are not familiar with this style).

"I know how in js there is a degree of 'binding' scope and hiding functionality in closures." I'm not really talking about this, or JS in particular. I'm really just talking about the concept of a closure which you can find in many languages. Python already has closures (lambda), but why they can only be one expression instead of multiple lines seems somewhat arbitrary, besides maybe ease of implementing the language/problems specific to Python implementation (can you explain this one?). From a purely programming perspective, I shouldn't care about what a language has trouble with, I care about using high level and expressive constructs, I don't want to limit my expressiveness because of some technical issue in a language. Many languages implement closures efficiently.

"As an aside, would you say js scope/closure approach is a bit similar to the approach in R?" Haven't really used R, but in the languages I have used with closures, they all are basically the same. Really the wikipedia article on closures captures this.