bind

Namespace: FsToolkit.ErrorHandling
Function Signature:
('a -> Result<'b option, 'c>) -> Result<'a option, 'c> 
  -> Result<'b option, 'c>
Examples
Take the following function for example
// string -> Result<int option, string>
let tryParseInt (s: string) =
    match Int32.TryParse(s) with
    | true, i -> Ok(Some i)
    | false, _ -> Error "Could not parse string as int"
Example 1
let result =
    Ok(Some "123") // Result<string option, 'error>
    |> ResultOption.bind tryParseInt // Result<int option, 'error>
​
// Ok (Some 123)
Example 2
let result =
    Ok None // Result<string option, 'error>
    |> ResultOption.bind tryParseInt // Result<int option, 'error>
​
// Ok None
Example 3
let result =
    Ok(Some "bad things happened") // Result<string option, string>
    |> ResultOption.bind tryParseInt // Result<int option, string>
​
// Error "Could not parse string as int"
Example 4
let result =
    Error "bad things happened" // Result<string option, string>
    |> ResultOption.bind tryParseInt // Result<int option, string>
​
// Error "bad things happened"

apply

Computation Expression

Last modified 2mo ago