Question about Func's

[iyegoroff]

Why do you use types like Func<x, y, z> instead of (x -> y -> z) almost everywhere? It seems that second signature is easier to use:

with Func's

let renderItem (item: FlatListRenderItemInfo<'a>) =
  //...

R.flatList items
  [ RenderItem (Func<_, _>renderItem)
    KeyExtractor (Func<_, _, _>(fun item _ -> itemKey item)) ]

with arrows

let renderItem (item: FlatListRenderItemInfo<'a>) =
  //...

R.flatList items
  [ RenderItem renderItem
    KeyExtractor (fun item _ -> itemKey item) ]

[forki]

/cc @alfonsogcnunez @MangelMaxime

iyegoroff notifications@github.com schrieb am Mo., 11. Juni 2018, 04:52:

Why do you use types like Func<x, y, z> instead of (x -> y -> z) almost everywhere? It seems that second signature is easier to use:

with Func's

let renderItem (item: FlatListRenderItemInfo<'a>) = //...

R.flatList items [ RenderItem (Func<, >renderItem) KeyExtractor (Func<, , >(fun item -> itemKey item)) ]

with arrows

let renderItem (item: FlatListRenderItemInfo<'a>) = //...

R.flatList items [ RenderItem renderItem KeyExtractor (fun item _ -> itemKey item) ]

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[Zaid-Ajaj]

@iyegoroff if Func is being used in the API then it is out-dated. x -> y -> z should be used because it compiles down to the uncurried version of the function i.e. function (x, y) { return z; } for better inter-operability and it can still be partially applied.

[alfonsogarciacaro]

It's as @Zaid-Ajaj says :) Originally Fable compiled curried F# functions as nested JS anonymous functions (x => y => z) so we used Func<int,int,int> to indicate the function wasn't curried. In most cases the conversion from curried F# function to Func (aka delegate in .NET) was done automatically by the F# compiler but in others it was hindering usability, so from Fable 1.x on, we're trying not to compile curried functions as nested lambdas. And in most cases you don't need to use Func in signatures any more.

[iyegoroff]

@Zaid-Ajaj , @alfonsogarciacaro thanks for the answers!