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Witnesses made visible in FCS by dsyme · Pull Request #9510 · dotnet/fsharp · Gi...

 3 years ago
source link: https://github.com/dotnet/fsharp/pull/9510
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alfonsogarciacaro commented on Jun 24

@dsyme I've built FCS from this branch and I'm testing it with Fable: https://github.com/fable-compiler/Fable/blob/1ed140e4ffacf232ca5d14e5bee2e48e5b1c3570/src/Fable.Transforms/FSharp2Fable.fs#L548-L562

It's working but I'm facing a couple of problems:

  • The index from WitnessArg doesn't seem to be reliable. Every time I've found the pattern is always -1, so I've to make a guess and assume it's 0 if the enclosing scope does contain witnesses.
  • When visiting some expressions the following line is throwing the exception: "The lists had different lengths. list2 is 1 element shorter than list1":
    let convertedArgs = (argExprs, argTypes) ||> List.map2 (fun expr expectedTy -> mkCoerceIfNeeded g expectedTy (tyOfExpr g expr) expr)

For example I get the exception when trying to parse any of the following texts (note the message always says "list2 is 1 element shorter than list1"):

type Point =
    { x: int; y: int }
    static member Zero = { x=0; y=0 }
    static member Neg(p: Point) = { x = -p.x; y = -p.y }
    static member (+) (p1, p2) = { x= p1.x + p2.x; y = p1.y + p2.y }

type MyNumber =
    | MyNumber of int
    static member Zero = MyNumber 0
    static member (+) (MyNumber x, MyNumber y) =
        MyNumber(x + y)
    static member DivideByInt (MyNumber x, i: int) =
        MyNumber(x / i)

type MyNumberWrapper =
    { MyNumber: MyNumber }

module ArrayTests =
    testCase "Array.average works with custom types" <| fun () ->
        [|MyNumber 1; MyNumber 2; MyNumber 3|] |> Array.average |> equal (MyNumber 2)

    testCase "Array.averageBy works with custom types" <| fun () ->
        [|{ MyNumber = MyNumber 5 }; { MyNumber = MyNumber 4 }; { MyNumber = MyNumber 3 }|]
        |> Array.averageBy (fun x -> x.MyNumber) |> equal (MyNumber 4)

    testCase "Array.sum with non numeric types works" <| fun () ->
        let p1 = {x=1; y=10}
        let p2 = {x=2; y=20}
        [|p1; p2|] |> Array.sum |> equal {x=3;y=30}

    testCase "Array.sumBy with non numeric types works" <| fun () ->
        let p1 = {x=1; y=10}
        let p2 = {x=2; y=20}
        [|p1; p2|] |> Array.sumBy Point.Neg |> equal {x = -3; y = -30}

    testCase "Array.sum with non numeric types works II" <| fun () ->
        [|MyNumber 1; MyNumber 2; MyNumber 3|] |> Array.sum |> equal (MyNumber 6)

    testCase "Array.sumBy with non numeric types works II" <| fun () ->
        [|{ MyNumber = MyNumber 5 }; { MyNumber = MyNumber 4 }; { MyNumber = MyNumber 3 }|]
        |> Array.sumBy (fun x -> x.MyNumber) |> equal (MyNumber 12)

I will try to convert these into tests for this repository and send a PR tomorrow.


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