Module:Highest archive number: Difference between revisions

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This module is rated as ready for general use. It has reached a mature form and is thought to be relatively bug-free and ready for use wherever appropriate. It is ready to mention on help pages and other Wikipedia resources as an option for new users to learn. To reduce server load and bad output, it should be improved by sandbox testing rather than repeated trial-and-error editing.

This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing.

This module depends on the following other modules:

Module:Exponential search

This module finds the highest archive number for a given set of numbered archive pages. The only input required is the prefix of the archive set. For example, for Talk:France/Archive 1, Talk:France/Archive 2, etc., the prefix would be "Talk:France/Archive ".

The module uses an exponential search algorithm, so it will make relatively few expensive function calls even for large numbers of archives. (The expensive function call is necessary to determine whether an individual archive exists.) For 1-10 archive pages, the module typically uses 4-6 expensive function calls; for 20-100 archives, it uses 6-12 calls; and for hundreds of archives, it uses 12-20 calls.

Because the module uses an exponential search, no gaps are allowed in the archive numbers; if there are any gaps, then the module may return the number of any archive page that exists where the following archive page does not exist. However, archive numbers do not have to start at 1; if they start at a higher number, you can specify this number in the start parameter.

Usage

From wikitext

From wikitext this module is usually used via the {{highest archive number}} template. However, it is also possible to use it directly from invoke with the syntax {{#invoke:highest archive number|main|prefix|start=start}}.

From Lua

Load the module with the following code:

local mHAN = require('Module:Highest archive number')

You can then use it like this:

mHAN._main(prefix, start)

The prefix variable is the prefix of the archive set.

Examples

#invoke code	Lua code	Result
`{{#invoke:highest archive number\|main\|Wikipedia:Administrators' noticeboard/IncidentArchive}}`	`mHAN._main("Wikipedia:Administrators' noticeboard/IncidentArchive")`
`{{#invoke:highest archive number\|main\|Talk:Byzantine Empire/Archive }}`	`mHAN._main("Talk:Byzantine Empire/Archive ")`
`{{#invoke:highest archive number\|main\|Wikipedia talk:WikiProject Chemicals/Archive \|start=2005}}`	`mHAN._main("Wikipedia talk:WikiProject Chemicals/Archive ", 2005)`

The above documentation is transcluded from Module:Highest archive number/doc.
Editors can experiment in this module's sandbox and testcases pages.
Subpages of this module.

-- This module finds the highest existing archive number for a set of talk
-- archive pages.

local p = {}

local function pageExists(page)
	local success, title = pcall(mw.title.new, page)
	return success and title and title.exists
end

local function findHighestArchive(prefix, i, lower, upper)
	if pageExists(prefix .. tostring(i)) then
		lower = i
		if upper and i + 1 == upper then
			return i
		elseif upper then
			i = math.floor(lower + (upper - lower) / 2)
		else
			i = i * 2
		end
		return findHighestArchive(prefix, i, lower, upper)
	else
		upper = i
		lower = lower or math.floor(i / 2)
		i = math.floor(lower + (upper - lower) / 2)
		return findHighestArchive(prefix, i, lower, upper)
	end
end

p.find = findHighestArchive

function p._main(args)
end

function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame)
	return p._main(args)
end

return p