Add function! (function-bang) keyword to computation expressions

[lucasteles]

Add function! (function-bang) keyword to computation expressions

I propose we extend computation expressions with a new keyword, function! (function-bang), that functions a match! For example, instead of writing:

let createResult = 
    connection  |> createEntityAsync entity
 
match! createResult with
| Error msg -> ..
| Ok _ -> ...

connection
    |> createEntityAsync entity
    |> function!
       | Error msg -> ...
       | Ok _ -> ...

Pros and Cons

Pros: Aids code readability in specialized cases.

Cons: increases complexity.

Extra information

First suggested here

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• This is not a breaking change to the F# language design
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[jwosty]

Interestingly enough, the implementation of match! actually desugars to let! followed by a function instead of match, which is also exactly what this suggestion would do. So this would be pretty easy.

[dsyme]

I am generally not in favour of extensive use of function - very occasionally, but it should be rare. So in all cases I would prefer an explicit match!.

For this reason, I will close this.