Calculate a tax rates using F#

taxOfUs.fs

let taxOf salary taxRates = 
	((0m,0)::taxRates, taxRates) 
		||> Seq.zip 
		 |> Seq.map(fun ((_, prevBand),(rate, band)) -> (prevBand, rate, band))
		 |> Seq.sumBy(fun (prevBand, rate, band) -> 
			match salary with 
				| x when x < prevBand -> 0m
				| x when x > band -> decimal(band - prevBand) * rate
				| x -> decimal(x - prevBand) * rate
			)

//define custom tax bands and rates
let israelTaxRates = [
	0.10m, 5070; 
	0.14m, 8660; 
	0.23m, 14070; 
	0.30m, 21240; 
	0.33m, 40230; 
	0.45m, System.Int32.MaxValue]

//use currying to build a higher order function to calculate Israel Tax Rates
let taxOfIsrael salary = israelTaxRates |> taxOf salary

//taxOfIsrael 5000   = 500.00
//taxOfIsrael 5800   = 609.20

Ah.. this is beautiful!