Module:Archive list

-- This module implements in Lua, and adds a few -- new features.

-- Process a numeric argument to make sure it is a positive -- integer. local function processNumArg( num ) if num then num = tonumber( num ) if type( num ) == 'number' then num = math.floor( num ) if num >= 0 then return num end end end return nil end

-- Checks whether a page exists, going through pcall -- in case we are over the expensive function limit. local function checkPageExists( title ) if not title then error('No title passed to checkArchiveExists', 2) end local noError, titleObject = pcall(mw.title.new, title) if not noError then -- If we are over the expensive function limit then assume -- that the page doesn't exist. return false else if titleObject then return titleObject.exists else return false -- Return false if given a bad title. end end end

-- Checks every nth archive to see if it exists, and returns the -- number of the first archive that doesn't exist. It is -- necessary to do this in batches because each check is an -- expensive function call, and we want to avoid making too many -- of them so as not to go over the expensive function limit. local function checkArchives( prefix, n, start ) local i = start local exists = true while exists do       exists = checkPageExists( prefix .. tostring( i ) ) if exists then i = i + n       end end return i end

-- Return the biggest archive number, using checkArchives -- and starting in intervals of 1000. This should get us a -- maximum of 500,000 possible archives before we hit the -- expensive function limit. local function getBiggestArchiveNum( prefix, max ) -- Return the value for max if it is specified. max = processNumArg( max ) if max then return max end -- Otherwise, detect the largest archive number. local check1000 = checkArchives( prefix, 1000, 1 ) if check1000 == 1 then return 0 -- Return 0 if no archives were found. end local check200 = checkArchives( prefix, 200, check1000 - 1000 ) local check50 = checkArchives( prefix, 50, check200 - 200 ) local check10 = checkArchives( prefix, 10, check50 - 50 ) local check1 = checkArchives( prefix, 1, check10 - 10 ) -- check1 is the first page that doesn't exist, so we want to   -- subtract it by one to find the biggest existing archive. return check1 - 1 end

-- Get the archive link prefix (the title of the archive pages -- minus the number). local function getPrefix( root, prefix, prefixSpace ) local ret = root or mw.title.getCurrentTitle.prefixedText ret = ret .. '/'   if prefix then ret = ret .. prefix if prefixSpace == 'yes' then ret = ret .. ' '       end else ret = ret .. 'Archive ' end return ret end

-- Get the number of archives to put on one line. Set to -- math.huge if there should be no line breaks. local function getLineNum( links, nobr ) local linksToNum = tonumber( links ) local lineNum if nobr == 'yes' or (links and not linksToNum) then lineNum = math.huge -- If links is a number, process it. Negative values and expressions -- such as links=8/2 produced some interesting values with the old -- template, but we will ignore those for simplicity. elseif type(linksToNum) == 'number' and linksToNum >= 0 then -- The old template rounded down decimals to the nearest integer. lineNum = math.floor( linksToNum ) if lineNum == 0 then -- In the old template, values of links between 0 and 0.999 -- suppressed line breaks. lineNum = math.huge end else lineNum = 10 -- Default to 10 links. end return lineNum end

-- Gets the prefix to put before the archive links. local function getLinkPrefix( prefix, space ) -- Get the link prefix. local ret = '' if type(prefix) == 'string' then ret = prefix if space == 'yes' then ret = ret .. ' '       end end return ret end

-- Get the number to start listing archives from. local function getStart( start ) start = processNumArg( start ) if start then return start else return 1 end end

-- Generates the list of archive links. glargs.max must be either zero (for -- no archives) or a positive integer value. local function generateLinks( glargs ) if type( glargs ) ~= 'table' or not glargs.max or not glargs.prefix then error('insufficient arguments passed to generateLinks', 2) end -- If there are no archives yet, return a message and a   -- link to create Archive one. if glargs.max == 0 then return 'no archives yet (create)' end -- Return an html error if the start number is greater than the -- maximum number. local start = glargs.start or 1 if start > glargs.max then return ' Start value "'            .. tostring( start )             .. '" is greater than the most recent archive number "'             .. tostring( glargs.max )             .. '". '   end local linkPrefix = glargs.linkPrefix or '' local sep = glargs.sep or ', ' local lineNum = glargs.lineNum or 10 local lineSep = glargs.lineSep or ' '

-- Generate the archive links. local lineCounter = 1 -- The counter to see whether we need a line break or not. local ret = {} -- A table containing the strings to be returned. for archiveNum = start, glargs.max do       local link = mw.ustring.format(            '%s%d',            glargs.prefix, archiveNum, linkPrefix, archiveNum        ) table.insert( ret, link ) -- If we don't need a new line, output a comma. We don't need -- a comma after the last link. if lineCounter < lineNum and archiveNum < glargs.max then table.insert( ret, sep ) lineCounter = lineCounter + 1 -- Output new lines if needed. We don't need a new line after -- the last link. elseif lineCounter >= lineNum and archiveNum < glargs.max then table.insert( ret, lineSep ) lineCounter = 1 end end return table.concat( ret ) end

-- Get the archive data and pass it to generateLinks. local function _main( args ) local prefix = getPrefix( args.root, args.prefix, args.prefixspace ) local max = getBiggestArchiveNum( prefix, args.max ) local lineNum = getLineNum( args.links, args.nobr ) local linkPrefix = getLinkPrefix( args.linkprefix, args.linkprefixspace ) local start = getStart( args.start ) local glargs = { start = start, max = max, prefix = prefix, linkPrefix = linkPrefix, sep = args.sep, lineNum = lineNum, lineSep = args.linesep }   return generateLinks( glargs ) end

-- A wrapper function to make getBiggestArchiveNum available from -- #invoke. local function _count( args ) local prefix = getPrefix( args.root, args.prefix, args.prefixspace ) local archiveMax = getBiggestArchiveNum( prefix ) return archiveMax end

function makeWrapper( func ) return function( frame ) -- If we are being called from #invoke, get the args from #invoke -- if they exist, or else get the arguments passed to the parent -- frame. Otherwise, assume the arguments are being passed directly -- in from another module or from the debug console. 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 -- Ignore blank values for parameters other than "links", -- which functions differently depending on whether it is       -- blank or absent. local args = {} for k, v in pairs( origArgs ) do           if k == 'links' or v ~= '' then args[k] = v           end end return func( args ) end end

return { main = makeWrapper( _main ), count = makeWrapper( _count ) }