Combining Partial Active Patterns 1

pattern_match2_fsharp_blog_17.fsx

open System
open System.Globalization
    
type LogMessage =
    | Info of DateTime * Message : string
    | Warning of DateTime * Message : string
    | Error of DateTime * Code : int * Message : string

let (|Date|_|) (input : string) =
    let success, date = 
        DateTime.TryParseExact(input, [|"dd/MM/yyyy HH:mm:ss"|], CultureInfo.InvariantCulture, DateTimeStyles.None)
    if success then Some(date) else None

let (|Int|_|) (input : string) =
    let success, int = Int32.TryParse input
    if success then Some(int) else None