Module:Section link

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

-- This module implements {{section link}}.
require('strict');

local checkType = require('libraryUtil').checkType

local p = {}

local function makeSectionLink(page, section, display)
    display = display or section
    page = page or ''
    -- MediaWiki doesn't allow these in `page`, so only need to do for `section`
    if type(section) == 'string' then
        section = string.gsub(section, "{", "{")
        section = string.gsub(section, "}", "}")
    end
    return string.format('[[%s#%s|%s]]', page, section, display)
end

local function normalizeTitle(title)
    title = mw.ustring.gsub(mw.ustring.gsub(title, "'", ""), '"', '')
    title = mw.ustring.gsub(title, "%b<>", "")
    return mw.title.new(title).prefixedText
end

function p._main(page, sections, options, title)
    -- Validate input.
    checkType('_main', 1, page, 'string', true)
    checkType('_main', 3, options, 'table', true)
    if sections == nil then
        sections = {}
    elseif type(sections) == 'string' then
        sections = {sections}
    elseif type(sections) ~= 'table' then
        error(string.format(
            "type error in argument #2 to '_main' " ..
            "(string, table or nil expected, got %s)",
            type(sections)
        ), 2)
    end
    options = options or {}
    title = title or mw.title.getCurrentTitle()

    -- Deal with blank page names elegantly
    if page and not page:find('%S') then
        page = nil
        options.nopage = true
    end

    -- Make the link(s).
    local isShowingPage = not options.nopage
    if #sections <= 1 then
        local linkPage = page or ''
        local section = sections[1] or 'Notes'
        local display = '§&nbsp;' .. section
        if isShowingPage then
            page = page or title.prefixedText
            if options.display and options.display ~= '' then
                if normalizeTitle(options.display) == normalizeTitle(page) then
                    display = options.display .. ' ' .. display
                else
                    error(string.format(
                        'Display title "%s" was ignored since it is ' ..
                        "not equivalent to the page's actual title",
                        options.display
                    ), 0)
                end
            else
                display = page .. ' ' .. display
            end
        end
        return makeSectionLink(linkPage, section, display)
    else
        -- Multiple sections. First, make a list of the links to display.
        local ret = {}
        for i, section in ipairs(sections) do
            ret[i] = makeSectionLink(page, section)
        end

        -- Assemble the list of links into a string with mw.text.listToText.
        -- We use the default separator for mw.text.listToText, but a custom
        -- conjunction. There is also a special case conjunction if we only
        -- have two links.
        local conjunction
        if #sections == 2 then
            conjunction = '&#8203; and '
        else
            conjunction = ', and '
        end
        ret = mw.text.listToText(ret, nil, conjunction)

        -- Add the intro text.
        local intro = '§§&nbsp;'
        if isShowingPage then
            intro = (page or title.prefixedText) .. ' ' .. intro
        end
        ret = intro .. ret

        return ret
    end
end

function p.main(frame)
    local yesno = require('Module:Yesno')
    local args = require('Module:Arguments').getArgs(frame, {
        wrappers = 'Template:Section link',
        valueFunc = function (key, value)
            value = value:match('^%s*(.-)%s*$') -- Trim whitespace
            -- Allow blank first parameters, as the wikitext template does this.
            if value ~= '' or key == 1 then
                return value
            end
        end
    })

    for k, v in pairs(args) do                                                    -- replace underscores in the positional parameter values
        if 'number' == type(k) then
            if not yesno (args['keep-underscores']) then                        -- unless |keep-underscores=yes
                args[k] = mw.uri.decode (v, 'WIKI');                            -- percent-decode; replace underscores with space characters
            else
                args[k] = mw.uri.decode (v, 'PATH');                            -- percent-decode; retain underscores
            end
        end
    end

    -- Sort the arguments.
    local page
    local sections, options = {}, {}
    for k, v in pairs(args) do
        if k == 1 then
            -- Doing this in the loop because of a bug in [[Module:Arguments]]
            -- when using pairs with deleted arguments.
            page = mw.text.decode(v, true)
        elseif type(k) == 'number' then
            sections[k] = v
        else
            options[k] = v
        end
    end
    
    options.nopage = yesno (options.nopage);                                    -- make boolean
    
    -- Extract section from page, if present
    if page then
        local p, s = page:match('^(.-)#(.*)$')
        if p then page, sections[1] = p, s end
    end

    -- Compress the sections array.
    local function compressArray(t)
        local nums, ret = {}, {}
        for num in pairs(t) do
            nums[#nums + 1] = num
        end
        table.sort(nums)
        for i, num in ipairs(nums) do
            ret[i] = t[num]
        end
        return ret
    end
    sections = compressArray(sections)

    return p._main(page, sections, options)
end

return p