FsToolkit.ErrorHandling

ResultOption Infix Operators
FsToolkit.ErrorHandling provides the standard infix operators for the map (<!>), apply (<*>) & bind (>>=) functions of ResultOption.
Namespace: FsToolkit.ErrorHandling.Operator.ResultOption
In addition to these, it also offers an another infix operator <*^> which has the following function singature.
Result<('a -> 'b) option, 'c> -> Result<'a, 'c> 
  -> Result<'b option, 'c>
Examples
Example 1
Assume that we have the following function,
// int -> int -> int -> int
let add a b c = a + b + c
Then using ResultOption infix operators, we can achieve the following
// returns - Ok (Some 42)
let opResult : Result<int option, string> =
  add
  <!> (Ok (Some 30)) 
  <*> (Ok (Some 10)) 
  <*> (Ok (Some 2))
Using the <*^> operator, the above code snippet can be written as
let opResult : Result<int option, string> =
  add3
  <!> (Ok (Some 30)) 
  <*^> (Ok 10) 
  <*^> (Ok 2)
Example 2
The ResultOption.map2 example can be written using ResultOption infix operators as below
let toCreatePostRequest (dto :CreatePostRequestDto) = 
​
  // Result<Location option, string>
  let locationR = 
    location
    <!> Option.traverseResult Latitude.TryCreate dto.Latitude
    <*> Option.traverseResult Longitude.TryCreate dto.Longitude
​
  // Result<Tweet, string>
  let tweetR = Tweet.TryCreate dto.Tweet
​
  // Result<CreatePostRequest, string>
  Result.map2 createPostRequest tweetR locationR

Computation Expression

AsyncResult

Contents

ResultOption Infix Operators
Examples
Example 1
Example 2