default values is one of my pet-peeves after using Python regularly. I wish more languages would let you just do something like defdo_thing(arg=default_value) without hoops like builder pattern, function overloading, or whatnot
I mean, the go-to approach in Lisp, for example, is to have null as the default value (which doubles for false in there). And check for that in the function.
In Lisp, at least the Emacs Lisp with which I have experience, it’s customary to put in nil (Lisp’s null) for any omitted arguments in the middle that you can’t be arsed to specify — aside from just leaving off arguments at the end. In JS, typing in undefined in every such case would probably be an annoyance, so I’m guessing coders need to check for both undefined and null in these circumstances.
Overall, it’s remarkable how Lisp teaches one to be much more relaxed about programming practices than is typical for mainstream languages. Design patterns? Data structures? Shit, just pass in a list or an assoc array, and maybe a function here and there. Also everything is an expression, enjoy your ternary (if) at any point anywhere.
Kotlin also lets you do
fun x() = y()I have no idea why you’d need that especially since return y() is pretty easy, but… I want it!
(Actually, I guess a super simple way of overloading a method, like fun x() = x(defaultValue) could be neat)
This can also be a side product for code blocks being expressions instead of statements.
In rust for example they are, so it’s not rare to see functions like:
fn add_one(x: i32) -> i32 { x+1 }This lets you do amazing things like:
let x = if y < 0.0 { 0.0 } else { y }which is the same as
x = y < 0.0 ? 0.0 : yBut is much better for more complex logic. So you can forget about chaining 3-4 ternary operations in a single line.
Lisp programmers seeing these ‘amazing things’:
But yeah, every time I’m trying to do a ternary in Lua, I miss being able to just throw in an
if. Thankfully it can be amended with Fennel.default values is one of my pet-peeves after using Python regularly. I wish more languages would let you just do something like
def do_thing(arg=default_value)without hoops like builder pattern, function overloading, or whatnot(Kotlin does support that, with the same
fun do_thing(arg: Int = 2)syntax.)I mean, the go-to approach in Lisp, for example, is to have null as the default value (which doubles for false in there). And check for that in the function.
That sounds awfully similar to JavaScript, which uses undefined as default values.
In Lisp, at least the Emacs Lisp with which I have experience, it’s customary to put in
nil(Lisp’s null) for any omitted arguments in the middle that you can’t be arsed to specify — aside from just leaving off arguments at the end. In JS, typing inundefinedin every such case would probably be an annoyance, so I’m guessing coders need to check for bothundefinedandnullin these circumstances.Overall, it’s remarkable how Lisp teaches one to be much more relaxed about programming practices than is typical for mainstream languages. Design patterns? Data structures? Shit, just pass in a list or an assoc array, and maybe a function here and there. Also everything is an expression, enjoy your ternary
(if)at any point anywhere.