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− | -- This module provides functions for getting the target of a redirect page. | + | ---- This module accepts the name of a single page. It determines if the page is a redirect; if so it looks up the page, extracts the target, and returns the target name as text. Its usage is {{#invoke:redirect|main|redirect-page-name}}. The template neither takes nor gives square brackets, so to show the result as a link use [[{{#invoke:redirect|main|redirect-page-name}}]]. An error is produced if the redirect does not exist, but for versatility no error is given if the file is not a redirect (returns the original text) or if the file name is blank (returns blank). |
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− | local p = {}
| + | p={} |
| | | |
− | -- Gets a mw.title object, using pcall to avoid generating script errors if we
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− | -- are over the expensive function count limit (among other possible causes).
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− | local function getTitle(...)
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− | local success, titleObj = pcall(mw.title.new, ...)
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− | if success then
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− | return titleObj
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− | else
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− | return nil
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− | end
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− | end
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− |
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− | -- Gets the name of a page that a redirect leads to, or nil if it isn't a
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− | -- redirect.
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− | function p.getTargetFromText(text)
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− | return string.match(
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− | text,
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− | "^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)%]%]"
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− | ) or string.match(
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− | text,
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− | "^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)|[^%[%]]-%]%]"
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− | )
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− | end
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− |
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− | -- Gets the target of a redirect. If the page specified is not a redirect,
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− | -- returns nil.
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− | function p.getTarget(page, fulltext)
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− | -- Get the title object. Both page names and title objects are allowed
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− | -- as input.
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− | local titleObj
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− | if type(page) == 'string' or type(page) == 'number' then
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− | titleObj = getTitle(page)
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− | elseif type(page) == 'table' and type(page.getContent) == 'function' then
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− | titleObj = page
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− | else
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− | error(string.format(
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− | "bad argument #1 to 'getTarget'"
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− | .. " (string, number, or title object expected, got %s)",
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− | type(page)
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− | ), 2)
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− | end
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− | if not titleObj or not titleObj.isRedirect then
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− | return nil
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− | end
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− |
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− | -- Find the target by using string matching on the page content.
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− | local target = p.getTargetFromText(titleObj:getContent() or "")
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− | if target then
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− | local targetTitle = getTitle(target)
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− | if targetTitle then
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− | if fulltext then
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− | return targetTitle.fullText
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− | else
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− | return targetTitle.prefixedText
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− | end
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− | else
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− | return nil
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− | end
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− | else
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− | -- The page is a redirect, but matching failed. This indicates a bug in
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− | -- the redirect matching pattern, so throw an error.
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− | error(string.format(
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− | 'could not parse redirect on page "%s"',
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− | fulltext and titleObj.fullText or titleObj.prefixedText
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− | ))
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− | end
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− | end
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− |
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− | --[[
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− | -- Given a single page name determines what page it redirects to and returns the
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− | -- target page name, or the passed page name when not a redirect. The passed
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− | -- page name can be given as plain text or as a page link.
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− | --
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− | -- Returns page name as plain text, or when the bracket parameter is given, as a
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− | -- page link. Returns an error message when page does not exist or the redirect
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− | -- target cannot be determined for some reason.
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− | --]]
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− | function p.luaMain(rname, bracket, fulltext)
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− | if type(rname) ~= "string" or not rname:find("%S") then
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− | return nil
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− | end
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− | bracket = bracket and "[[%s]]" or "%s"
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− | rname = rname:match("%[%[(.+)%]%]") or rname
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− | local target = p.getTarget(rname, fulltext)
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− | local ret = target or rname
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− | ret = getTitle(ret)
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− | if ret then
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− | if fulltext then
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− | ret = ret.fullText
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− | else
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− | ret = ret.prefixedText
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− | end
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− | return bracket:format(ret)
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− | else
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− | return nil
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− | end
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− | end
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− |
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− | -- Provides access to the luaMain function from wikitext.
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| function p.main(frame) | | function p.main(frame) |
− | local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
| + | args=frame.args |
− | return p.luaMain(args[1], args.bracket, args.fulltext) or ''
| + | parent=frame.getParent(frame) |
− | end | + | if parent then pargs = parent.args else pargs={} end |
− | | + | local rname=args[1] or pargs[1] or "" |
− | -- Returns true if the specified page is a redirect, and false otherwise.
| + | if redirect=="" then return "" end |
− | function p.luaIsRedirect(page)
| + | local rpage=mw.title.new(rname) |
− | local titleObj = getTitle(page)
| + | local err="" |
− | if not titleObj then
| + | if rpage then -- avoid possibly expensive FileExists if we don't have anything |
− | return false
| + | if rpage.id ~= 0 then |
− | end
| + | -- if rpage.fileExists then |
− | if titleObj.isRedirect then
| + | if rpage.isRedirect then |
− | return true
| + | return (tostring(mw.ustring.find(tostring(rpage.getContent(rpage)),"REDIRECT(.-)%[%[(.-)%]%]")) or [=[<span style="text-color:red;">[[Module:redirect]] error: failed to understand - [[]=] .. rname .. [=[]]</span]=]) |
− | else
| + | else return rname -- not a redirect so leave the original text (for some general-purpose template use) |
− | return false
| + | end |
− | end
| + | -- else err="File does not exist: " |
− | end | + | -- end |
− | | + | else err="File not found (id=0): " |
− | -- Provides access to the luaIsRedirect function from wikitext, returning 'yes' | + | end |
− | -- if the specified page is a redirect, and the blank string otherwise. | + | else err="File not found (mw.title.new failed)" |
− | function p.isRedirect(frame)
| + | end |
− | local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
| + | return [=[<span style="text-color:red;">[[Module:redirect]] error: ]=] .. err .. [=[ - [[]=] .. rname .. [=[]]</span>]=] |
− | if p.luaIsRedirect(args[1]) then
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− | return 'yes'
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− | else
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− | return ''
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− | end
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| end | | end |
| | | |
| return p | | return p |