趣味编程：静夜思（F#3.0版）

open System

let print (text : string) offset =
    query {
        for (c, i) in Seq.zip text (seq {0 .. text.Length - 1}) do
        groupValBy (string c) (i % offset) into g
        select (g |> Seq.reduce (fun c1 c2 -> c2 + "|" + c1))
    } |> Seq.iter (printfn "%s")

print "床前明月光疑是地上霜举头望明月低头思故乡" 5

//低|举|疑|床
//头|头|是|前
//思|望|地|明
//故|明|上|月
//乡|月|霜|光