-- This is a simple module to strip categories from wikitext. It does

-- not support nested links or magic words like __TOC__, etc. Even so,

-- it should still handle most categories.



local p = {}



-- Detects if a category link is valid or not. If it is valid,

-- the function returns the blank string. If not, the input

-- is returned with no changes.

local function processCategory( all, submatch )

    local beforePipe = mw.ustring.match( submatch, '^(.-)[%s_]*|[%s_]*.-$' )

    beforePipe = beforePipe or submatch

    if mw.ustring.match( beforePipe, '[%[%]<>{}%c\n]' ) then

        return all

    else

        return ''

    end

end



-- Preprocess the content if we aren't being called from #invoke,

-- and pass it to gsub to remove valid category links.

local function suppress( content, isPreprocessed )

    if not isPreprocessed then

        content = mw.getCurrentFrame():preprocess( content )

    end

    content = mw.ustring.gsub(

        content,

        '(%[%[[%s_]*[cC][aA][tT][eE][gG][oO][rR][yY][%s_]*:[%s_]*(.-)[%s_]*%]%])',

        processCategory

    )

    return content

end



-- Get the content to suppress categories from, and find

-- whether the content has already been preprocessed. (If the

-- module is called from #invoke, it has been preprocessed already.)

function p.main( frame )

    local content, isPreprocessed

    if frame == mw.getCurrentFrame() then

        content = frame:getParent().args1

        if frame.args1 then

            content = frame.args1

        end

        isPreprocessed = true

    else

        content = frame

        isPreprocessed = false

    end

    return suppress( content, isPreprocessed )

end



return p