Module:Random: Difference between revisions

Revision as of 15:51, 28 November 2013

Latest revision as of 16:32, 11 November 2015

(4 intermediate revisions by 2 users not shown)

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-- This module contains a number of functions that make use of random numbers.

local pcfg = {}

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-- Configuration

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-- 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

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-- End configuration

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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

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-- Helper functions

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local function setRandomSeed()

-- Set the seed for the random number generator. This works well on the English Wikipedia due to the high

-- edit rate, but should also work well on smaller wikis due to the variability of os.time() (the current time)

-- and os.clock() (the time the program takes to run).

math.randomseed(mw.site.stats.edits + mw.site.stats.pages + os.time() + math.floor(os.clock() * 1000000000))

end

local function raiseError(msg)

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end

local function getRandoml.number(args)

-- Gets a random number. It is left to the calling function to set the random seed.

first = tonumber(args[1])

second = tonumber(args[2])

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return math.random()

end

end

function p._number(args)

-- Returns a random number. Will return different random numbers even on the same page.

setRandomSeed()

return getRandom(args)

end

function p._same_number(args)

-- Returns a random number. Will return the same random number on the same page if called with the same parameters.

-- If you are using a very low traffic wiki this might not update frequently enough, and you may get the same "random"

-- number many times in a row. (Until someone makes a new edit, or creates a new user account, etc.)

-- To fix this, replace the line beginning with "local seed" with the following code:

--

-- local seed = math.floor(os.time() / 60)

--

-- This makes the seed change once a minute. (The "60" is the number of seconds between one seed and the next.)

-- You can decrease the value if you want the seed to update more frequently. However, smaller values increase the risk

-- that the function may return different values, especially for calls to Lua that take several seconds to complete.

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)

return getRandom(args)

end

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function pl._datedate(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.

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-- 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.

setRandomSeed()

local lang = mw.language.getContentLanguage()

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--------------------------------------------------------------------------------------

local function p.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.

setRandomSeed()

-- The lowest possible value is 0, and the highest possible is the length of the array.

for i = #t, 2, -1 do

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

return t

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

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-- 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.

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local function makeRandomList(args)

local list = removeBlanks(args)

list = p.randomizeArray(list, tonumber(args.limit))

return list

end

function pl._itemitem(args)

-- Returns a random item from a numbered list.

setRandomSeed()

local list = removeBlanks(args)

iflocal #listlen >= 1 then#list

if len >= 1 then

return list[math.random(#list)]

return list[math.random(len)]

end

end

function pl._listlist(args)

-- Randomizes a list and concatenates the result with a separator.

setRandomSeed()

local list = makeRandomList(args)

local sep = makeSeparator(args.sep or args.separator)

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end

function pl._text_listtext_list(args)

-- Randomizes a list and concatenates the result, text-style. Accepts separator and conjunction arguments.

setRandomSeed()

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

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--------------------------------------------------------------------------------------

function pl.html_list(args, listType)

-- Randomizes a list and turns it into an HTML list. Uses [[Module:List]].

setRandomSeed()

listType = listType or 'bulleted'

local listArgs = makeRandomList(args) -- Arguments for [[Module:List]].

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end

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-- 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

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-- Process arguments from #invoke

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end

end

return p[funcName].main(funcName, args, listType)

end

end

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-- Process arguments for other functions.

local otherFuncs = {'number', 'same_number', 'date', 'item', 'list', 'text_list'}

for _, funcName in ipairs(otherFuncs) do

p[funcName] = makeWrapper('_' .. funcName)

end