Console Module

The Console module exposes basic text I/O through host-provided runtime externs.

Console.writeLine : string -> unit

Writes one line of text to standard output.

Console.writeLine "hello"
Console.writeLine $"args={Env.Arguments}"

Console.readLine : unit -> string option

Reads one line from standard input. Returns None on end-of-input.

match Console.readLine () with
| Some text -> Console.writeLine $"echo: {text}"
| None -> Console.writeLine "no input"

Notes

• Console.writeLine accepts a string, so convert non-string values explicitly or use string interpolation.
• Console.readLine is a zero-argument function and should be called as Console.readLine ().
• Console.readLine returning None usually means stdin is exhausted or unavailable.
• Console I/O is provided by the host runtime, not by the pure language core.

Example

Console.writeLine "What is your name?"

let greeting =
  match Console.readLine () with
  | Some name -> $"Hello {name}"
  | None -> "Hello"

Console.writeLine greeting