-- This module converts a number into its written English form.

-- For example, "2" becomes "two", and "79" becomes "seventy-nine".



local getArgs = require('Module:Arguments').getArgs



local p = {}



local max = 100 -- The maximum number that can be parsed.



local ones = {

	0 = 'zero',

	1 = 'one',

	2 = 'two',

	3 = 'three',

	4 = 'four',

	5 = 'five',

	6 = 'six',

	7 = 'seven',

	8 = 'eight',

	9 = 'nine'

}



local specials = {

	10 = 'ten',

	11 = 'eleven',

	12 = 'twelve',

	13 = 'thirteen',

	15 = 'fifteen',

	18 = 'eighteen',

	20 = 'twenty',

	30 = 'thirty',

	40 = 'forty',

	50 = 'fifty',

	60 = 'sixty',

	70 = 'seventy',

	80 = 'eighty',

	90 = 'ninety',

	100 = 'one hundred'

}



local formatRules = {

	{num = 90, rule = 'ninety-%s'},

	{num = 80, rule = 'eighty-%s'},

	{num = 70, rule = 'seventy-%s'},

	{num = 60, rule = 'sixty-%s'},

	{num = 50, rule = 'fifty-%s'},

	{num = 40, rule = 'forty-%s'},

	{num = 30, rule = 'thirty-%s'},

	{num = 20, rule = 'twenty-%s'},

	{num = 10, rule = '%steen'}

}



function p.main(frame)

	local args = getArgs(frame)

	local num = tonumber(args1])

	local success, result = pcall(p._main, num)

	if success then

		return result

	else

		return string.format('<strong class="error">Error: %s</strong>', result) -- "result" is the error message.

	end

	return p._main(num)

end



function p._main(num)

	if type(num) ~= 'number' or math.floor(num) ~= num or num < 0 or num > max then

		error('input must be an integer between 0 and ' .. tostring(max), 2)

	end

	-- Check for numbers from 0 to 9.

	local onesVal = onesnum

	if onesVal then

		return onesVal

	end

	-- Check for special numbers.

	local specialVal = specialsnum

	if specialVal then

		return specialVal

	end

	-- Construct the number from its format rule.

	onesVal = onesnum % 10

	if not onesVal then

		error('Unexpected error parsing input ' .. tostring(num))

	end

	for i, t in ipairs(formatRules) do

		if num >= t.num then

			return string.format(t.rule, onesVal)

		end

	end

	error('No format rule found for input ' .. tostring(num))

end



return p