diamonds.fs

let R2 n = 
	let xs = [-n .. n]
	seq { for x in xs do for y in xs do yield x,y }

let TaxicabNorm (x, y) =  abs x + abs y
let radius = 10

let indexedLetters =
    ['A' .. 'Z'] |> Seq.mapi (fun i l -> i,l) 

let findLetter xcord =
	let i,l = Seq.find(fun (i, l) -> i = abs xcord) indexedLetters 
	l

let diamond = (R2 radius) 
			|> Seq.filter (fun x -> TaxicabNorm x = radius) 
			|> Seq.map( fun (x, y) -> (x,y),findLetter x)

let whiteLines n = 
	let xs = [|-n .. n|]
	[| for i in -n .. n -> (Array.map (fun _ -> '.') xs) |]
	
let drawing = whiteLines radius

for point in diamond do
	let (x,y), letter = point
	let yindex = Array.findIndex (fun elem -> y = elem) [|-radius .. radius|]
	let xindex = Array.findIndex (fun elem -> x = elem) [|-radius .. radius|]
	drawing.[xindex].[yindex] <- letter
	
let printArray (arr: char array) = new string (arr) |> sprintf "%A" |> Dump

for line in drawing do
	printArray line