Another neat thing is that these functions are n-ary, and that includes 0 args. So (+) => 0 (additive identity) and (*) => 1 (multiplicative identity). Little things like this are missing from languages like Python and make functional programming worse than it should be.
Oh wow, this is truly great! Would you have a link to the code behind `(+)` and `(*)` ?
(In my functional programming languages, `reduce` also requires passing an initial value, like `foldl (+) 0 [1, 2, 3]`. But surely it should get a monoid instead of two separate arguments for the operation and the starting value!)
Yeah, it always annoys me to have to pass an initial argument. The idea of identities is built into Lisps and seems conspicuously missing from other languages and I don't know why. In Python and JS people have to write stuff like `lambda x: x` over and over again. The identity function is surely special enough to get its own name.
I know this isn't the identity function, but it's the same idea and a feeling I get when using Lisps that the language is kind of "complete". Including the identity function and having built in 0-ary functions where it makes sense are examples of this.
