[swift-users] Trouble with function properties

[Doug Hill]

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 <mailto: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
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> swift-users at swift.org <mailto:swift-users at swift.org>
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> -- 
> -Saagar Jha

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