Module:Redirect

Documentation for this module may be created at Module:Redirect/doc

 ---- 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).

p={}

function p.main(frame)
   args=frame.args
   parent=frame.getParent(frame)
   if parent then pargs = parent.args else pargs={} end
   local rname=args[1] or pargs[1] or ""
   local bracket=args.bracket or pargs.bracket
   local bb = "";local be= "" -- store brackets if restoring to an output if bracket option is set
   if rname then
       if mw.ustring.gsub(rname,"%s","") == "" then return "" end
       if bracket then
           local strip=mw.ustring.match(rname,"%[%[(.+)%]%]")
           if strip then rname=strip;bb="[[";be="]]" end
       end
       else return ""
   end
   local rpage=mw.title.new(rname)
   local err=""
   if rpage then -- avoid possibly expensive FileExists if we don't have anything
      if rpage.id ~= 0 then
       --  if rpage.fileExists then
            if rpage.isRedirect then
               return (bb.. tostring(mw.ustring.match(tostring(rpage.getContent(rpage)),"[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt].-%[%[(.-)%]%]")..be) or [=[<span style="text-color:red;">[[Module:redirect]] error: failed to understand - [[]=] .. rname .. [=[]]</span]=])
            else return rname -- not a redirect so leave the original text (for some general-purpose template use)
            end
      --   else err="File does not exist: "
      --   end
      else err="File not found (id=0):"
      end
   else err="File not found (mw.title.new failed)"
   end
   return [=[<span style="text-color:red;">[[Module:redirect]] error: ]=] .. err .. [=[ - [[]=] .. rname .. [=[]]</span>]=]
end

return p