Module:Parent

Documentation for this module may be created at Module:Parent/Documentation

local p = {}

-- returns a sequence of all headings in title
function headingList( title )
    -- insert leading newline to make our pattern simpler
    local content = "\n" .. title:getContent()
    local names = {}
    for level, name in string.gmatch( content, "\n(=+)%s*([^\n][^\n]-)%s*%1\n" ) do
        table.insert( names, name )
    end
    -- Also match HTML tags with anchor ids, e.g. <span id="A">
    -- that may or may not be self closing
    for _, name in string.gmatch( content, "<%w+ .-id=(['\"])([^%1][^%1]-)%1.-/?>" ) do
        table.insert( names, name )
    end

    return names
end

--[[
Checks if the enclosing page has the given section. This executes on the
top-level page being processed, not the template containing the invoke call.

Usage: {{#invoke:parent|ifSection|section|then|else}}

Arguments:
section - the section name to check for (Required)
then - text to display if the page has the section (Optional)
else - text to display if the page does not have the section (Optional)
]]
function p.ifSection( frame )
    local title = mw.title.getCurrentTitle()
    local heading = frame.args[1]
    if not heading or string.len( heading ) == 0 then
    	error( 'Argument 1 to ifSection is required.' )
    end

    local headings = headingList( title )
    local foundSection = false
    
    for i, v in ipairs( headings ) do
        if heading == v then
            foundSection = true
            break
        end
    end

    if foundSection then
        return frame.args[2] or ''
    else
        return frame.args[3] or ''
    end
end

--[[
Produces an Alphabet Table of Contents, with links to lettered sections
if they exist on the page, otherwise the letters are not linked.

Usage: {{#invoke:parent|alphabetTOC}}
]]
function p.alphabetTOC( frame )
    local headings = headingList( mw.title.getCurrentTitle() )
    local ltrs = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }
    local wikitext = '{| border=0 cellpadding=4 class="plainlinks" id="alphabetTOC_table" style="font-size:2em;margin:auto;background:#f0f0f0;text-align:center"\n'

    local first = true
    for i, l in ipairs( ltrs ) do
        local found = false
        for j, h in ipairs( headings ) do
            if l == h then
                found = true
                break
            end
        end

        if l == 'N' then
            -- start a new row for N-Z
            wikitext = wikitext .. "\n|-\n"
            first = true
        end

        if first then
            wikitext = wikitext .. "|"
            first = false
        else
            wikitext = wikitext .. "||"
        end

        if found then
            wikitext = wikitext .. string.format( '[[#%s|%s]]', l, l )
        else
            wikitext = wikitext .. l
        end
    end

    return wikitext .. "\n|}"
end

return p