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Swift is like Kotlin

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Re: Swift is like Kotlin

#41

Post by derefr »

Watabou wrote: post #23
kodfodrasz wrote: post #7

Could someone tell me the meaning of _ in this Swift code: func greet(_ name: String,_ day: String) -> String { return "Hello \(name), today is \(day)." } greet("Bob", "Tuesday") In me prior experience usually _ denoted an unused parameter/variable. Also: I find the string interpolation syntax ugly... The syntax choices in Swift are curious, but not the most aesthetical/practical in my opinion.

Swift has both external and internal parameter names for functions. This is to make API design more readable, easier to parse through. For example, you can have a function like so: func greet(with greeting: String, to personName: String) { print("\(greeting), \(personName)!") } In the above code, "with" and "to" are external names, and are only available when calling the function but are not available inside the func…

Is there a parse-time reason that they required the "_" syntax, rather than simply:

    func greet(greeting: String, personName: String) {
        print("\(greeting), \(personName)!")
    }

Re: Swift is like Kotlin

#42

Post by saghm »

Watabou wrote: post #23
kodfodrasz wrote: post #7

Could someone tell me the meaning of _ in this Swift code: func greet(_ name: String,_ day: String) -> String { return "Hello \(name), today is \(day)." } greet("Bob", "Tuesday") In me prior experience usually _ denoted an unused parameter/variable. Also: I find the string interpolation syntax ugly... The syntax choices in Swift are curious, but not the most aesthetical/practical in my opinion.

Swift has both external and internal parameter names for functions. This is to make API design more readable, easier to parse through. For example, you can have a function like so: func greet(with greeting: String, to personName: String) { print("\(greeting), \(personName)!") } In the above code, "with" and "to" are external names, and are only available when calling the function but are not available inside the func…

Having never used Swift, it feels like the syntax is being optimized for the less-common case; are named parameters considered the "default" choice in Swift, and is using different external names so common that it's worth cluttering the syntax for functions without external parameters in order to make the their own syntax easier?

Re: Swift is like Kotlin

#43

Post by thramp »

derefr wrote: post #41
Watabou wrote: post #23

Earlier quoted context omitted.

Swift has both external and internal parameter names for functions. This is to make API design more readable, easier to parse through. For example, you can have a function like so: func greet(with greeting: String, to personName: String) { print("\(greeting), \(personName)!") } In the above code, "with" and "to" are external names, and are only available when calling the function but are not available inside the func…

Is there a parse-time reason that they required the "_" syntax, rather than simply: func greet(greeting: String, personName: String) { print("\(greeting), \(personName)!") }

It's a side effect of labeled arguments. The caller would use the function greet as `greet(greeting: "Hello", personName: "Alice")`.

Re: Swift is like Kotlin

#44

Post by tomfitz »

derefr wrote: post #38
tomfitz wrote: post #28

Earlier quoted context omitted.

An alternative approach is Guava's Range class: Range.closed(1,5) == [1,5] Range.open(1,5) == (1,5) Range.openClosed(1,5) == (1,5] Range.closedOpen(1,5) == [1,5) Range.greaterThan(1) == (1,infinity) Range.atLeast(1) == [1,infinity) That class always strikes me as having high power-to-weight. It has methods like encloses(anotherRange), contains(aValue), and others. https://google.github.io/guava/releases/19.0/api/docs…

What does a Guava two-Integer-element array literal look like?

Sorry, I didn't explain myself well.

Range.closed(1,5) is the syntax used to refer to what a mathematician would call [1,5].

Guava is just a Java library. In Java 9, a two-Integer-element list literal will be List.of(9000, 9001).

Re: Swift is like Kotlin

#45

Post by proyb2 »

seanwilson wrote: post #4
cpfohl wrote: post #3

Earlier quoted context omitted.

What do you like about it? I was actually thinking the opposite... EDIT: Genuinely curious, this is not meant to troll or start a war. I like the more explicit feeling `count-1`. I'd use either...

It confused me as well. "0.. is less than count"?

I believe it was discussed in Swift Evolution, not confusing.

    0...1 //0 to 1
Note: triple dot.

    0..2 //error: repl.swift:1:2: error: use of unresolved operator '..'


    0..

Re: Swift is like Kotlin

#46

Post by dbaupp »

saghm wrote: post #35
sillysaurus3 wrote: post #10

Earlier quoted context omitted.

Yes, but the corresponding design decision would be "0..=n". Swift's "0...n" is a bit less obvious. Also, exclusivity is almost always what you want, so "0..n" should just default to exclusivity and "0...n" could be inclusive.

As an alternative opinion, I personally hate when ranges are exclusive by default. In addition to it feeling somewhat unintuitive to me that I need to use range(0, 6) to include 5, it also makes downward ranges quite awkward, e.g. needing range(5, -1) to count from 5 to 0.

Exclusive by default is designed to fit with 0-based indexing (0..length(v), instead 0..(length(v)-1)). That said, this thinking is less relevant in languages with iterators/ranges and doubly so ones that offer a way to explicitly, but abstractly, iterate over the indices of a vector/array.

On the point of downward ranges, you can often reverse the range explicitly, rather than swapping the endpoints, like reversed(range(0, 6)) or range(0, 6)[::-1] in Python (vs. range(5, -1, -1)). Of course, this isn't nearly as syntactically nice as range(5, 0)... but that comes with its own problems: automatically iterating backwards in ranges has been really annoying every time I've encountered it (mainly in R), requiring extra care and a pile of extra ifs and/or mins & maxs.

Re: Swift is like Kotlin

#47

Post by mixmastamyk »

saghm wrote: post #35
sillysaurus3 wrote: post #10

Earlier quoted context omitted.

Yes, but the corresponding design decision would be "0..=n". Swift's "0...n" is a bit less obvious. Also, exclusivity is almost always what you want, so "0..n" should just default to exclusivity and "0...n" could be inclusive.

As an alternative opinion, I personally hate when ranges are exclusive by default. In addition to it feeling somewhat unintuitive to me that I need to use range(0, 6) to include 5, it also makes downward ranges quite awkward, e.g. needing range(5, -1) to count from 5 to 0.

It's due to the zero-based indexing, right? In something like lua, that starts at 1, inclusive makes more sense.

Re: Swift is like Kotlin

#48

Post by zem »

throwaway91111 wrote: post #22
zem wrote: post #2

0..<count is a lovely little piece of language design

I can't tell whether this is sarcasm or not. What does the '<' mean in this case? I'm assuming an exclusive upper bound.

it's not. i've never used swift, and the meaning was instantly obvious - i'd call that a very elegant solution to a common problem i've seen in several languages.

Re: Swift is like Kotlin

#49

Post by Cyph0n »

solidsnack9000 wrote: post #24

There does seem to be broad agreement across a range of typed languages -- TypeScript, Swift, Kotlin, ES6 + Flow -- about notations for classes, control flow and data structure declaration. But true convergence remains far away...

Don't forget that Scala preceded all of the languages you've listed, which in my opinion shows where the inspiration came from for some of them. Of course, I'm sure that Scala drew inspiration from some of its predecessors.
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