99 Bottles of Beer

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real language

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Alternative Versions

Version	Author	Date	Comments	Rate
Cleaner still	Don Syme	12/07/06	0
Recursive implementation	Alec Zorab	07/04/09	0
Tail Recursion Call	Simon Kang	06/22/09	0
lists and lambda's	Kyle Eppley	05/04/10	0

Comments

  said on 03/11/09 16:24:59

Those who prefer not to generate a list of the verses before printing them, could iterate over a list of integers instead, replacing the last line with

List.iter (fun v -> printfn "%s" (verse v)) [99..-1..0]

Using function composition, which is a neat functional language feature, verse and printfn can be composed into a new function by (verse >> printfn "%s", so we can write

List.iter (fun v -> (verse >> printfn "%s" v) [99..-1..0]

Function pipelining, the |> operator in F#, is yet another neat feature of functional languages, which lets you chain functions together, passing the result of one function on as the argument of the next. It looks like this:

[99..-1..0] |> List.iter (fun v -> v |> verse |> printfn "%s"

  said on 03/11/09 16:29:14

OOOPS! The above comment became a bit cryptic, since some of my paranthesis expressions turned into smilies. This is a new attempt:

Those who prefer not to generate a list of the verses before printing them, could iterate over a list of integers instead, replacing the last line with

List.iter (fun v -> printfn "%s" (verse v)) [99..-1..0]

Using function composition, which is a neat functional language feature, verse and printfn can be composed into a new function by ( verse >> printfn "%s" ), so we can write

List.iter (fun v -> ( verse >> printfn "%s" ) v) [99..-1..0]

Function pipelining, the |> operator in F#, is yet another neat feature of functional languages, which lets you chain functions together, passing the result of one function on as the argument of the next. It looks like this:

[99..-1..0] |> List.iter ( fun v -> v |> verse |> printfn "%s" )

 kyle eppley said on 05/03/10 17:52:38

Curious... I posted an almost identical version last july and never herd or seen it...

module BeerProg /// required for compile error in fsi

let a = " of beer " /// strings used in order of apperance
let b = "on the wall"
let c = "take one down pass it around"
let z = "No more bottles of beer on the wall, no more bottles of beer.\n" +
"Go to the store and buy some more, 99 bottles of beer on the wall.\n"

let bs n = /// correct notation of bottles verse n
match n with /// use match to correct the tense
| 0 -> "no more bottles" /// 0
| 1 -> "1 bottle" /// 1
| _ -> n.ToString() + " bottles" //// 99-2

let beer n = /// print beer each line then last verse
List.iter (fun i -> /// iterate list, printf for each item in the list following it
printfn "%s%s%s, %s%s\n%s, %s%s%s\n" (bs i) a b (bs i) a c (bs (i-1)) a b)
[n..(-1)..1] /// create list 99 down to 1
printfn "%s" z /// last verse since it is unique

beer 99;;

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