Module:Random
-- This module contains a number of functions that make use of random numbers. local cfg = {}
-- Configuration
-- Set this to true if your wiki has a traffic rate of less than one edit every two minutes or so. -- This will prevent the same "random" number being generated many times in a row until a new edit is made -- to the wiki. This setting is only relevant if the |same= parameter is set. cfg.lowTraffic = false -- If cfg.lowTraffic is set to true, and the |same= parameter is set, this value is used for the refresh rate of the random seed. -- This is the number of seconds until the seed is changed. Getting this right is tricky. If you set it too high, the same number -- will be returned many times in a row. If you set it too low, you may get different random numbers appearing on the same page, -- particularly for pages that take many seconds to process. cfg.seedRefreshRate = 60
-- End configuration
local p = {} -- For functions available from other Lua modules. local l = {} -- For functions not available from other Lua modules, but that need to be accessed using table keys. local yesno = require('Module:Yesno') local makeList = require('Module:List').makeList
-- Helper functions
local function raiseError(msg)
-- This helps to generate a wikitext error. It is the calling function's responsibility as to how to include it in the output.
return mw.ustring.format('Module:Random error: %s.', msg)
end
-- random number function
local function getBigRandom(l, u)
-- Gets a random integer between l and u, and is not limited to RAND_MAX.
local r = 0
local n = 2^math.random(30) -- Any power of 2.
local limit = math.ceil(53 / (math.log(n) / math.log(2)))
for i = 1, limit do
r = r + math.random(0, n - 1) / (n^i)
end
return math.floor(r * (u - l + 1)) + l
end function l.number(args)
-- Gets a random number.
first = tonumber(args[1])
second = tonumber(args[2])
-- This needs to use if statements as math.random won't accept explicit nil values as arguments.
if first then
if second then
if first > second then -- Second number cannot be less than the first, or it causes an error.
first, second = second, first
end
return getBigRandom(first, second)
else
return getBigRandom(1, first)
end
else
return math.random()
end
end
-- Date function
function l.date(args)
-- This function gets random dates, and takes timestamps as positional arguments.
-- With no arguments specified, it outputs a random date in the current year.
-- With two arguments specified, it outputs a random date between the timestamps.
-- With one argument specified, the date is a random date between the unix epoch (1 Jan 1970) and the timestamp.
-- The output can be formatted using the "format" argument, which works in the same way as the #time parser function.
-- The default format is the standard Wikipedia timestamp.
local lang = mw.language.getContentLanguage()
local function getDate(format, ts)
local success, date = pcall(lang.formatDate, lang, format, ts)
if success then
return date
end
end
local function getUnixTimestamp(ts)
local unixts = getDate('U', ts)
if unixts then
return tonumber(unixts)
end
end
local t1 = args[1]
local t2 = args[2]
-- Find the start timestamp and the end timestamp.
local startTimestamp, endTimestamp
if not t1 then
-- Find the first and last second in the current year.
local currentYear = tonumber(getDate('Y'))
local currentYearStartUnix = tonumber(getUnixTimestamp('1 Jan ' .. tostring(currentYear)))
local currentYearEndUnix = tonumber(getUnixTimestamp('1 Jan ' .. tostring(currentYear + 1))) - 1
startTimestamp = '@' .. tostring(currentYearStartUnix) -- @ is used to denote Unix timestamps with lang:formatDate.
endTimestamp = '@' .. tostring(currentYearEndUnix)
elseif t1 and not t2 then
startTimestamp = '@0' -- the Unix epoch, 1 January 1970
endTimestamp = t1
elseif t1 and t2 then
startTimestamp = t1
endTimestamp = t2
end
-- Get Unix timestamps and return errors for bad input (or for bugs in the underlying PHP library, of which there are unfortunately a few)
local startTimestampUnix = getUnixTimestamp(startTimestamp)
local endTimestampUnix = getUnixTimestamp(endTimestamp)
if not startTimestampUnix then
return raiseError('"' .. tostring(startTimestamp) .. '" was not recognised as a valid timestamp')
elseif not endTimestampUnix then
return raiseError('"' .. tostring(endTimestamp) .. '" was not recognised as a valid timestamp')
elseif startTimestampUnix > endTimestampUnix then
return raiseError('the start date must not be later than the end date (start date: "' .. startTimestamp .. '", end date: "' .. endTimestamp .. '")')
end
-- Get a random number between the two Unix timestamps and return it using the specified format.
local randomTimestamp = getBigRandom(startTimestampUnix, endTimestampUnix)
local dateFormat = args.format or 'H:i, d F Y (T)'
local result = getDate(dateFormat, '@' .. tostring(randomTimestamp))
if result then
return result
else
return raiseError('"' .. dateFormat .. '" is not a valid date format')
end
end
-- List functions
local function randomizeArray(t, limit)
-- Randomizes an array. It works by iterating through the list backwards, each time swapping the entry -- "i" with a random entry. Courtesy of Xinhuan at http://forums.wowace.com/showthread.php?p=279756 -- If the limit parameter is set, the array is shortened to that many elements after being randomized. -- The lowest possible value is 0, and the highest possible is the length of the array. local len = #t for i = len, 2, -1 do local r = math.random(i) t[i], t[r] = t[r], t[i] end if limit and limit < len then local ret = {} for i, v in ipairs(t) do if i > limit then break end ret[i] = v end return ret else return t end
end local function removeBlanks(t)
-- Removes blank entries from an array so that it can be used with ipairs.
local ret = {}
for k, v in pairs(t) do
if type(k) == 'number' then
table.insert(ret, k)
end
end
table.sort(ret)
for i, v in ipairs(ret) do
ret[i] = t[v]
end
return ret
end local function makeSeparator(sep)
if sep == 'space' then
-- Include an easy way to use spaces as separators.
return ' '
elseif sep == 'newline' then
-- Ditto for newlines
return '\n'
elseif type(sep) == 'string' then
-- If the separator is a recognised MediaWiki separator, use that. Otherwise use the value of sep if it is a string.
local mwseparators = {'dot', 'pipe', 'comma', 'tpt-languages'}
for _, mwsep in ipairs(mwseparators) do
if sep == mwsep then
return mw.message.new( sep .. '-separator' ):plain()
end
end
return sep
end
end local function makeRandomList(args)
local list = removeBlanks(args) list = randomizeArray(list, tonumber(args.limit)) return list
end function l.item(args)
-- Returns a random item from a numbered list.
local list = removeBlanks(args)
local len = #list
if len >= 1 then
return list[math.random(len)]
end
end function l.list(args)
-- Randomizes a list and concatenates the result with a separator. local list = makeRandomList(args) local sep = makeSeparator(args.sep or args.separator) return table.concat(list, sep)
end function l.text_list(args)
-- Randomizes a list and concatenates the result, text-style. Accepts separator and conjunction arguments. local list = makeRandomList(args) local sep = makeSeparator(args.sep or args.separator) local conj = makeSeparator(args.conj or args.conjunction) return mw.text.listToText(list, sep, conj)
end function l.array(args)
-- Returns a Lua array, randomized. For use from other Lua modules. return randomizeArray(args.t, args.limit)
end
-- HTML list function
function l.html_list(args, listType)
-- Randomizes a list and turns it into an HTML list. Uses Module:List. listType = listType or 'bulleted' local listArgs = makeRandomList(args) -- Arguments for Module:List. for k, v in pairs(args) do if type(k) == 'string' then listArgs[k] = v end end return makeList(listType, listArgs)
end
-- The main function. Called from other Lua modules.
function p.main(funcName, args, listType)
-- Sets the seed for the random number generator and passes control over to the other functions.
local same = yesno(args.same)
if not same then
-- Generates a different number every time the module is called, even from the same page.
-- This is because of the variability of os.clock (the time in seconds that the Lua script has been running for).
math.randomseed(mw.site.stats.edits + mw.site.stats.pages + os.time() + math.floor(os.clock() * 1000000000))
else
if not cfg.lowTraffic then
-- Make the seed as random as possible without using anything time-based. This means that the same random number
-- will be generated for the same input from the same page - necessary behaviour for some wikicode templates that
-- assume bad pseudo-random-number generation.
local stats = mw.site.stats
local views = stats.views or 0 -- This is not always available, so we need a backup.
local seed = views + stats.pages + stats.articles + stats.files + stats.edits + stats.users + stats.activeUsers + stats.admins -- Make this as random as possible without using os.time() or os.clock()
math.randomseed(seed)
else
-- Make the random seed change every n seconds, where n is set by cfg.seedRefreshRate.
-- This is useful for low-traffic wikis where new edits may not happen very often.
math.randomseed(math.floor(os.time() / cfg.seedRefreshRate))
end
end
if type(args) ~= 'table' then
error('the second argument to p.main must be a table')
end
return l[funcName](args, listType)
end
-- Process arguments from #invoke
local function makeWrapper(funcName, listType)
-- This function provides a wrapper for argument-processing from #invoke.
-- listType is only used with p.html_list, and is nil the rest of the time.
return function (frame)
-- If called via #invoke, use the args passed into the invoking template, or the args passed to #invoke if any exist.
-- Otherwise assume args are being passed directly in from the debug console or from another Lua module.
local origArgs
if frame == mw.getCurrentFrame() then
origArgs = frame:getParent().args
for k, v in pairs(frame.args) do
origArgs = frame.args
break
end
else
origArgs = frame
end
-- Trim whitespace and remove blank arguments.
local args = {}
for k, v in pairs(origArgs) do
if type(v) == 'string' then
v = mw.text.trim(v)
end
if v ~= then
args[k] = v
end
end
return p.main(funcName, args, listType)
end
end -- Process arguments for HTML list functions. local htmlListFuncs = {
bulleted_list = 'bulleted', unbulleted_list = 'unbulleted', horizontal_list = 'horizontal', ordered_list = 'ordered', horizontal_ordered_list = 'horizontal_ordered'
} for funcName, listType in pairs(htmlListFuncs) do
p[funcName] = makeWrapper('html_list', listType)
end -- Process arguments for other functions. local otherFuncs = {'number', 'date', 'item', 'list', 'text_list'} for _, funcName in ipairs(otherFuncs) do
p[funcName] = makeWrapper(funcName)
end return p
