Module:Delink: Difference between revisions

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    Revision as of 07:03, 14 December 2015

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

    -- This module de-links most wikitext.
    
    require('Module:No globals')
    
    local p = {}
    
    local getArgs
    
    local function delinkReversePipeTrick(s)
        if s:match("^%[%[|.*[|\n]") then -- Check for newlines or multiple pipes.
            return s
        else
            return s:match("%[%[|(.*)%]%]")
        end
    end
    
    local function delinkPipeTrick(s)
        local linkarea, display = "", ""
        -- We need to deal with colons, brackets, and commas, per [[Help:Pipe trick]].
        
        -- First, remove the text before the first colon, if any.
        if s:match(":") then
            s = s:match("%[%[.-:(.*)|%]%]")
        -- If there are no colons, grab all of the text apart from the square brackets and the pipe.
        else
            s = s:match("%[%[(.*)|%]%]")
        end
        
        -- Next up, brackets and commas.
        if s:match("%(.-%)$") then -- Brackets trump commas.
            s = s:match("(.-) ?%(.-%)$")
        elseif s:match(",") then -- If there are no brackets, display only the text before the first comma.
            s = s:match("(.-),.*$")
        end
        return s
    end
    
    local function delinkWikilink(s)
        local result = s
        -- Deal with the reverse pipe trick.
        if result:match("%[%[|") then
            return delinkReversePipeTrick(result)
        end
        
        result = mw.uri.decode(result, "PATH") -- decode percent-encoded entities. Leave underscores and plus signs.
        result = mw.text.decode(result, true) -- decode HTML entities.
        
        -- Check for bad titles. To do this we need to find the
        -- title area of the link, i.e. the part before any pipes.
        local titlearea
        if result:match("|") then -- Find if we're dealing with a piped link.
            titlearea = result:match("^%[%[(.-)|.*%]%]")
        else
            titlearea = result:match("^%[%[(.-)%]%]")
        end
        -- Check for bad characters.
        if mw.ustring.match(titlearea, "[%[%]<>{}%%%c\n]") then
            return s
        end
        
        -- Check for categories, interwikis, and files.
        local colonprefix = result:match("%[%[(.-):.*%]%]") or "" -- Get the text before the first colon.
        local ns = mw.site.namespaces[colonprefix] -- see if this is a known namespace
        if mw.language.isKnownLanguageTag(colonprefix)
        or ( ns and ( ns.canonicalName == "File" or ns.canonicalName == "Category" ) ) then
            return ""
        end
        
        -- Remove the colon if the link is using the [[Help:Colon trick]].
        if result:match("%[%[:") then
            result = "[[" .. result:match("%[%[:(.*%]%])")
        end
        
        -- Deal with links using the [[Help:Pipe trick]].
        if mw.ustring.match(result, "^%[%[[^|]*|%]%]") then
            return delinkPipeTrick(result)
        end
        
        -- Find the display area of the wikilink
        if result:match("|") then -- Find if we're dealing with a piped link.
            result = result:match("^%[%[.-|(.+)%]%]")
            -- Remove new lines from the display of multiline piped links,
            -- where the pipe is before the first new line.
            result = result:gsub("\n", "")
        else
            result = result:match("^%[%[(.-)%]%]")
        end
    
        return result
    end
    
    local function delinkURL(s)
        -- Assume we have already delinked internal wikilinks, and that
        -- we have been passed some text between two square brackets [foo].
        
        -- If the text contains a line break it is not formatted as a URL, regardless of other content.
        if s:match("\n") then
            return s
        end
        
        -- Check if the text has a valid URL prefix and at least one valid URL character.
        local valid_url_prefixes = {"//", "http://", "https://", "ftp://", "gopher://", "mailto:", "news:", "irc://"} 
        local url_prefix
        for i,v in ipairs(valid_url_prefixes) do
            if mw.ustring.match(s, '^%[' .. v ..'[^"%s].*%]' ) then
                url_prefix = v
                break
            end
        end
        
        -- Get display text
        if not url_prefix then
            return s
        end
        s = s:match("^%[" .. url_prefix .. "(.*)%]") -- Grab all of the text after the URL prefix and before the final square bracket.
        s = s:match('^.-(["<> ].*)') or "" -- Grab all of the text after the first URL separator character ("<> ).
        s = mw.ustring.match(s, "^%s*(%S.*)$") or "" -- If the separating character was a space, trim it off.
        
        local s_decoded = mw.text.decode(s, true)
        if mw.ustring.match(s_decoded, "%c") then
            return s
        else    
            return s_decoded
        end
    end
    
    local function delinkLinkClass(s, pattern, delinkFunction)
        if not type(s) == "string" then
            error("Attempt to de-link non-string input.", 2)
        end
        if not ( type(pattern) == "string" and mw.ustring.sub(pattern, 1, 1) == "^" ) then
            error('Invalid pattern detected. Patterns must begin with "^".', 2)
        end
        -- Iterate over the text string, and replace any matched text. using the 
        -- delink function. We need to iterate character by character rather 
        -- than just use gsub, otherwise nested links aren't detected properly.
        local result = ""
        while s ~= '' do
            -- Replace text using one iteration of gsub.
            s = mw.ustring.gsub(s, pattern, delinkFunction, 1)
            -- Append the left-most character to the result string.
            result = result .. mw.ustring.sub(s, 1, 1)
            s = mw.ustring.sub(s, 2, -1)
        end
        return result
    end
    
    function p._delink(args)
        local text = args[1] or ""
        if args.refs == "yes" then
            -- Remove any [[Help:Strip markers]] representing ref tags. In most situations 
            -- this is not a good idea - only use it if you know what you are doing!
            text = mw.ustring.gsub(text, "UNIQ%w*%-ref%-%d*%-QINU", "")
        end
        if not (args.comments == "no") then
            text = text:gsub("<!%-%-.-%-%->", "") -- Remove html comments.
        end
        if not (args.wikilinks == "no") then
            text = delinkLinkClass(text, "^%[%[.-%]%]", delinkWikilink) -- De-link wikilinks.
        end
        if not (args.urls == "no") then
            text = delinkLinkClass(text, "^%[.-%]", delinkURL) -- De-link URLs.
        end
        if not (args.whitespace == "no") then
            -- Replace single new lines with a single space, but leave double new lines
            -- and new lines only containing spaces or tabs before a second new line.
            text = mw.ustring.gsub(text, "([^\n \t][ \t]*)\n([ \t]*[^\n \t])", "%1 %2")
            text = text:gsub("[ \t]+", " ") -- Remove extra tabs and spaces.
        end
        return text
    end
    
    function p.delink(frame)
        if not getArgs then
        	getArgs = require('Module:Arguments').getArgs
        end
        return p._delink(getArgs(frame, {wrappers = 'Template:Delink'}))
    end
    
    return p