Reading the thread.. I wonder if we need "nil" at all, why not use (just a
question, not a suggestion) .none ? I.e. now we can use nil and .none in
the same situations, .none is just 2 symbols longer, '.none' highlight that
Optional is a special type (that there is .some(T) in Optional), no
confusion if it is related to pointers etc.
var i : Int? = 10
if i != .none { print(i) }
i = .none
print(i)
var i : Int? = 10
if i != nil { print(i) }
i = nil
print(i)
i.e. the same thing expressed in 2 different but similar ways. Probably I'm
missing something.
On 08.06.2016 12:33, J. Charles M. N. via swift-evolution wrote:
I'am not either for removing nil nor renaming it none, I think that they
are conceptually different things.
This syntactic sugar brings unfortunately many things around. One
fastidious thing is it multiple semantics: As null pointer. As none value.
I am personally not favorable for multiples semantics keywords.
Aside, if it come up to revisiting nil concept we should bring the other
chimera (unit, Void, bottom type etc).
--
J. Charles
Le 8 juin 2016 à 04:18, Muse M via swift-evolution
<[email protected] <mailto:[email protected]>> a écrit :
None would be similar to Null or nothing about the types in that sense
which None is not a type.
Nil would be interpret as Int, Float, String, etc
On Wed, Jun 8, 2016 at 9:17 AM, Dany St-Amant via swift-evolution
<[email protected] <mailto:[email protected]>> wrote:
No clue as to the origins, but if you insist on using none. you can do:
let a : Int? = .none
let b : Int? = .some(5)
Using the simpler
let a : Int? = nil
let b : Int? = 5
is just sugar.
Maybe it was foresight to prevent people from saying, if I can do:
let a : Int? = none
Why can't I do:
let b : Int? = some(5)
And then go a step further by asking for all enum to be access
without the leading dot; scary thought.
So it may be better to stick with '.none' and sugared 'nil'.
Dany
Le 7 juin 2016 à 20:16, Brandon Knope via swift-evolution
<[email protected] <mailto:[email protected]>> a écrit :
That's exactly the point I was going for.
none makes more sense in this context than nil in my opinion
Brandon
On Jun 7, 2016, at 8:10 PM, Saagar Jha <[email protected]
<mailto:[email protected]>> wrote:
Well, some is the opposite of none in that if I don’t have some, I
have none. nil is just a carry-over from Objective-C.
On Tue, Jun 7, 2016 at 5:07 PM Brandon Knope via swift-evolution
<[email protected] <mailto:[email protected]>> wrote:
I guess for me it comes down to this:
*Why were some and none chosen for as the cases for Optional?*
As an extension of that, why does nil then represent none
instead of the obvious none?
There has to be a reason why it's not:
enum Optional<T> {
case some(T)
case nil
}
None seems a lot more expressive and consistent with Optional.
I am comfortable and use to nil, but with swift being a new
language, I thought it was worth opening up a discussion about
possibly changing direction a little here.
Thanks,
Brandon
On Jun 7, 2016, at 7:57 PM, Jordan Rose <[email protected]
<mailto:[email protected]>> wrote:
There are NilLiteralConvertible types other than Optional, but
they’re dwindling now that pointer nullability is represented
by Optional. That said, I’m not convinced renaming “nil” is
worth it at this point. Similarity with other languages is
still a good thing.
It’s true that we might not have picked nil if it hadn’t been
for Objective-C, but that doesn’t make it an invalid choice.
There are lots of things in Swift we might have done
differently if it weren’t for Objective-C and Cocoa.
Jordan
On Jun 5, 2016, at 12:35, Brandon Knope via swift-evolution
<[email protected]
<mailto:[email protected]>> wrote:
Quick thought:
If optional has a .none case, wouldn't it be more consistent
to rename nil to none?
Also, would nil make it into Swift if not for other languages?
It also might make it somewhat clearer:
var someInt: Int? = none //looks less like a pointer and more
like a value of nothing
1. It is more consistent with the optional enum
2. The intent is arguably clearer
3. nil makes it seem like it's a pointer
4. Would nil be included if not for prior languages? Would
"none" have been chosen as the keyword if nil wasn't prior art?
One disadvantage is how close it is to .none, but with how
common nil/none is used, some syntactic sugar might make it
look nicer than always having the stray .
On vacation from Orlando, poolside, with a quick thought,
Brandon
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--
-Saagar Jha
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