[swift-users] Trouble with function properties

[Saagar Jha]

That’s how the Swift interpreter prints out closures. Try let testClosure =
{} in the REPL and you’ll get a similar result, except with different
arguments and return value due to {} being () -> ().


On Wed, Jun 15, 2016 at 8:13 PM Doug Hill via swift-users <
swift-users at swift.org> wrote:

> Thank you Saagar for looking over this code for me. I guess I got really
> caught up in the weird diagnostic message and assumed things weren’t
> working.
> Now I see that ‘afunc’ works as I expected:
>
> 60> g.afunc(numberRecords:1,userRecord:(13,9))
> 13 9
> $R3: (Int, (Int, Int)) = {
>   0 = 13
>   1 = {
>     0 = 9
>     1 = 1
>   }
> }
>
> Although I would be interested in why the compiler spits out the first
> message in the first place (e.g. the message with the strange description
> of afunc).
>
> Looking forward to see what I can do with Swift,
>
> Doug Hill
>
> On Jun 15, 2016, at 6:49 PM, Saagar Jha <saagarjha28 at gmail.com> wrote:
>
> `Gen` defines `afunc`, but you’re trying to access `aFunc`.
>
> On Wed, Jun 15, 2016 at 6:22 PM Doug Hill via swift-users <
> swift-users at swift.org> wrote:
>
>> I’m just starting to learn Swift and attempting to do some
>> functional-style programming. Specifically I’m learning how to create
>> generic algorithms that can be reused for many different types.
>> What I’m attempting to do is create a new object, passing functions to
>> the initializer. The class would store these functions as properties and
>> then use them for functional-style algorithms.
>>
>> The problem is I’m running into weird compiler errors/messages that I’m
>> trying to figure out. I'm hoping someone here can give me some pointers on
>> what these errors mean, and most likely what I’m doing wrong.
>>
>>   Apple Swift version 2.2 (swiftlang-703.0.18.8 clang-703.0.31) Target:
>> x86_64-apple-macosx10.9
>>
>> // =====================================================================
>> class Gen<InputKeyType, InputValueType, OutputKeyType, OutputValueType> {
>>     typealias func1Type = (numberRecords:InputKeyType, userRecord:
>> InputValueType ) -> (OutputKeyType, OutputValueType)
>>
>>     var afunc: func1Type
>>
>>     init( inFunc: func1Type ) {
>>         afunc = inFunc
>>     }
>> }
>>
>> var g: Gen<Int, (Int, Int), Int, (Int, Int)> =
>>     Gen( inFunc: { (numberRecords: Int, userRecord: (Int, Int)) -> (Int,
>> (Int, Int)) in
>>                 var b: Int = numberRecords
>>                 var (age, numFriends) = userRecord
>>                 print( (age), (numFriends) )
>>                 return (age, (numFriends, 1))
>>             }
>>     )
>> // =====================================================================
>>
>>
>> What I get as output from the Swift compiler are these confusing
>> messages. I included some print statements that hopefully gives some more
>> info about what’s happening.
>>
>> g: Gen<Int, (Int, Int), Int, (Int, Int)> = {
>>   afunc = 0x00000001012024d0 $__lldb_expr7`partial apply forwarder for
>> reabstraction thunk helper from @callee_owned (@unowned Swift.Int, @unowned
>> Swift.Int, @unowned Swift.Int) -> (@unowned (Swift.Int, (Swift.Int,
>> Swift.Int))) to @callee_owned (@in Swift.Int, @in (Swift.Int, Swift.Int))
>> -> (@out (Swift.Int, (Swift.Int, Swift.Int))) at repl6.swift
>> }
>>
>> print( (g) )
>> Gen<Swift.Int, (Swift.Int, Swift.Int), Swift.Int, (Swift.Int, Swift.Int)>
>>
>> print( (g.aFunc) )
>> repl.swift:48:9: error: value of type 'Gen<Int, (Int, Int), Int, (Int,
>> Int)>' has no member 'aFunc'
>>         ^ ~~~~~
>>
>>
>> There’s a good chance I’m doing something wrong but I don’t know how to
>> figure out what that problem is. Any ideas?
>>
>> Thanks.
>>
>> Doug
>> _______________________________________________
>> swift-users mailing list
>> swift-users at swift.org
>> https://lists.swift.org/mailman/listinfo/swift-users
>>
> --
> -Saagar Jha
>
>
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>
-- 
-Saagar Jha
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