모듈:NumberSpell

-- 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] = '0',
	[1] = '1',
	[2] = '2',
	[3] = '3',
	[4] = '4',
	[5] = '5',
	[6] = '6',
	[7] = '7',
	[8] = '8',
	[9] = '9'
}

local specials = {
	[10] = '10',
	[11] = '11',
	[12] = '12',
	[13] = '13',
	[15] = '15',
	[18] = '18',
	[20] = '20',
	[30] = '30',
	[40] = '40',
	[50] = '50',
	[60] = '60',
	[70] = '70',
	[80] = '80',
	[90] = '90',
	[100] = '100'
}

local formatRules = {
	{num = 90, rule = '9%s'},
	{num = 80, rule = '8%s'},
	{num = 70, rule = '7%s'},
	{num = 60, rule = '6%s'},
	{num = 50, rule = '5%s'},
	{num = 40, rule = '4%s'},
	{num = 30, rule = '3%s'},
	{num = 20, rule = '2%s'},
	{num = 10, rule = '1%s'}
}

function p.main(frame)
	local args = getArgs(frame)
	local num = tonumber(args[1])
	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 = ones[num]
	if onesVal then
		return onesVal
	end
	-- Check for special numbers.
	local specialVal = specials[num]
	if specialVal then
		return specialVal
	end
	-- Construct the number from its format rule.
	onesVal = ones[num % 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