From the linked page: "Before explaining how that program is written, let’s first make a small detour, and introduce the REPL (Read Eval Print Loop) tool, that

From the linked page: "Before explaining how that program is written, let’s first make a small detour, and introduce the REPL (Read Eval Print Loop) tool, that Elm — like many other functional languages — provides. The elm repl command starts it, like so:"