Infinite main loop in F#

Question

A usual pattern for CLI application is to run in infinite loop, until user types some quit command. Like, in C language:

while(1){
scanf("%c", &op);
    ...
    else if(op == "q")
        break;
    }

What would be the pattern for such console application in F# (tried to use tail recursrion, but failed)?

Answer 1

Typing in browser, thus may contain errors:

let rec main() = 
    let c = System.Console.ReadKey()
    if c.Key = System.ConsoleKey.Q then () // TODO: cleanup and exit
    else 
    // TODO: do something in main
    main()

Answer 2

Here's a none blocking version that responds to single key press.

open System

let rec main() = 
    // run code here

    // you may want to sleep to prevent 100% CPU usage
    // Threading.Thread.Sleep(1);

    if Console.KeyAvailable then
        match Console.ReadKey().Key with
        | ConsoleKey.Q -> ()
        | _ -> main()
    else
        main()

main()