Munging with Active Patterns

Have you checked out active patterns yet? C'mon! Here's what the code below might have looked like if I'd used them:

> open System;;

> open System.Text.RegularExpressions;;

> let re = new Regex("^(MON¦TUE¦WED¦THU¦FRI¦SAT¦SUN)", RegexOptions.Compiled);;

val re : Regex
> let (¦DataRow(¦_¦) (s : string) =
-     if re.IsMatch s
-         // Here I'd want to break the line down.
-     then Some(1, 2, "Hello!")
-     else None

val ( ¦DataRow¦_¦ ) : string -> (int * int * string) option

As I said earlier, Seq.choose will through out None, and I could then handle different kinds of data rows from the input:

> match "TUE" with
- ¦ DataRow(x, y, s) -> Console.WriteLine(s)
- // Additional cases here...
- ¦ _ -> Console.WriteLine("Got bupkes!");;
Hello!
val it : unit = ()