소스 파일명: TestIf.fs // Filename: TestIf.fs #light let printUsing x = printfn "Using: TestIf [number]" printfn "This determines whether the number is positive or not." let (|Float|_|) (str: string) = let mutable floatvalue = 0.0 if System.Double.TryParse(str, &floatvalue) then Some(floatvalue) else None let isPositveNegative = function | x when x > 0.0 -> "positive" | x when x "negative" |..