모듈:Math

--
This module provides a number of basic mathematical operations.
local yesno, getArgs -- lazily initialized
local p = {} -- Holds functions to be returned from #invoke, and functions to make available to other Lua modules.
local wrap = {} -- Holds wrapper functions that process arguments from #invoke. These act as intemediary between functions meant for #invoke and functions meant for Lua.
--
Helper functions used to avoid redundant code.
local function err(msg)
	-- Generates wikitext error messages.
	return mw.ustring.format('Formatting error: %s', msg)
end
local function unpackNumberArgs(args)
	-- Returns an unpacked list of arguments specified with numerical keys.
	local ret = {}
	for k, v in pairs(args) do
		if type(k) == 'number' then
			table.insert(ret, v)
		end
	end
	return unpack(ret)
end
local function makeArgArray(...)
	-- Makes an array of arguments from a list of arguments that might include nils.
	local args = {...} -- Table of arguments. It might contain nils or non-number values, so we can't use ipairs.
	local nums = {} -- Stores the numbers of valid numerical arguments.
	local ret = {}
	for k, v in pairs(args) do
		v = p._cleanNumber(v)
		if v then
			nums#nums + 1 = k
			argsk = v
		end
	end
	table.sort(nums)
	for i, num in ipairs(nums) do
		ret#ret + 1 = argsnum
	end
	return ret
end
local function fold(func, ...)
	-- Use a function on all supplied arguments, and return the result. The function must accept two numbers as parameters,
	-- and must return a number as an output. This number is then supplied as input to the next function call.
	local vals = makeArgArray(...)
	local count = #vals -- The number of valid arguments
	if count == 0 then return
		-- Exit if we have no valid args, otherwise removing the first arg would cause an error.
		nil, 0
	end
	local ret = table.remove(vals, 1)
	for _, val in ipairs(vals) do
		ret = func(ret, val)
	end
	return ret, count
end
--
Fold arguments by selectively choosing values (func should return when to choose the current "dominant" value).
local function binary_fold(func, ...)
	local value = fold((function(a, b) if func(a, b) then return a else return b end end), ...)
	return value
end
--
random
Generate a random number
Usage:
function wrap.random(args)
	local first = p._cleanNumber(args1)
	local second = p._cleanNumber(args2)
	return p._random(first, second)
end
function p._random(first, second)
	math.randomseed(mw.site.stats.edits + mw.site.stats.pages + os.time() + math.floor(os.clock() * 1000000000))
	-- math.random will throw an error if given an explicit nil parameter, so we need to use if statements to check the params.
	if first and second then
		if first  b end), ...)
	if max_value then
		return max_value
	end
end
--
median
Find the median of set of numbers
Usage:
OR
function wrap.median(args)
	return p._median(unpackNumberArgs(args))
end
function p._median(...)
	local vals = makeArgArray(...)
	local count = #vals
	table.sort(vals)
	if count == 0 then
		return 0
	end
	if p._mod(count, 2) == 0 then
		return (valscount/2 + valscount/2+1)/2
	else
		return valsmath.ceil(count/2)
	end
end
--
min
Finds the minimum argument
Usage:
OR
When used with no arguments, it takes its input from the parent
frame.  Note, any values that do not evaluate to numbers are ignored.
function wrap.min(args)
	return p._min(unpackNumberArgs(args))
end
function p._min(...)
	local min_value = binary_fold((function(a, b) return a = 14 then
		if order + p._precision(value_string) >= 14 then
			precision = 13 - order;
		end
	end
	-- If rounding off, truncate extra digits
	if precision = 9 then
		value = value * math.pow(10, -order)
		current_precision = current_precision + order
		precision = precision + order
		formatted_num = lang:formatNum(math.abs(value))
	else
		order = 0;
	end
	formatted_num = sign .. formatted_num
	-- Pad with zeros, if needed
	if current_precision  0 then
				local zero_sep = lang:formatNum(1.1)
				formatted_num = formatted_num .. zero_sep:sub(2,2)
				padding = precision
				if padding > 20 then
					padding = 20
				end
				formatted_num = formatted_num .. string.rep('0', padding)
			end
		else
			padding = precision - current_precision
			if padding > 20 then
				padding = 20
			end
			formatted_num = formatted_num .. string.rep('0', padding)
		end
	end
	-- Add exponential notation, if necessary.
	if order ~= 0 then
		-- Use proper unary minus sign rather than ASCII default
		if order ×10' .. order .. 
	end
	return formatted_num
end
--
divide
Implements the division operator
Usage:
--
function wrap.divide(args)
	local x = args1
	local y = args2
	local round = args.round
	local precision =  args.precision
	if not yesno then
		yesno = require('Module:Yesno')
	end
	return p._divide(x, y, yesno(round), precision)
end
function p._divide(x, y, round, precision)
	if y == nil or y == "" then
		return err("Empty divisor")
	elseif not tonumber(y) then
		if type(y) == 'string' and string.sub(y, 1, 1) == '<' then
			return y
		else
			return err("Not a number: " .. y)
		end
	elseif x == nil or x == "" then
		return err("Empty dividend")
	elseif not tonumber(x) then
		if type(x) == 'string' and string.sub(x, 1, 1) == '<' then
			return x
		else
			return err("Not a number: " .. x)
		end
	else
		local z = x / y
		if round then
			return p._round(z, 0)
		elseif precision then
			return p._round(z, precision)
		else
			return z	
		end
	end
end
--
Helper function that interprets the input numerically.  If the
input does not appear to be a number, attempts evaluating it as
a parser functions expression.
function p._cleanNumber(number_string)
	if type(number_string) == 'number' then
		-- We were passed a number, so we don't need to do any processing.
		return number_string, tostring(number_string)
	elseif type(number_string) ~= 'string' or not number_string:find('%S') then
		-- We were passed a non-string or a blank string, so exit.
		return nil, nil;
	end
	-- Attempt basic conversion
	local number = tonumber(number_string)
	-- If failed, attempt to evaluate input as an expression
	if number == nil then
		local success, result = pcall(mw.ext.ParserFunctions.expr, number_string)
		if success then
			number = tonumber(result)
			number_string = tostring(number)
		else
			number = nil
			number_string = nil
		end
	else
		number_string = number_string:match("^%s*(.-)%s*$") -- String is valid but may contain padding, clean it.
		number_string = number_string:match("^%+(.*)$") or number_string -- Trim any leading + signs.
		if number_string:find('^%-?0xX') then
			-- Number is using 0xnnn notation to indicate base 16; use the number that Lua detected instead.
			number_string = tostring(number)
		end
	end
	return number, number_string
end
--
Wrapper function that does basic argument processing. This ensures that all functions from #invoke can use either the current
frame or the parent frame, and it also trims whitespace for all arguments and removes blank arguments.
local mt = { __index = function(t, k)
	return function(frame)
		if not getArgs then
			getArgs = require('Module:Arguments').getArgs
		end
		return wrapk(getArgs(frame))  -- Argument processing is left to Module:Arguments. Whitespace is trimmed and blank arguments are removed.
	end
end }
return setmetatable(p, mt)