查看“︁模块:Yesno”︁的源代码

-- Imported from: https://en.wikipedia.org/wiki/Module:Yesno

-- Function allowing for consistent treatment of boolean-like wikitext input.
-- It works similarly to the template {{yesno}}.

return function (val, default)
    -- If your wiki uses non-ascii characters for any of "yes", "no", etc., you
    -- should replace "val:lower()" with "string.lower(val)" in the
    -- following line.
    val = type(val) == 'string' and val:lower() or val
    if val == nil then
        return nil
    elseif val == true
            or val == 'yes'
            or val == 'y'
            or val == 'true'
            or val == 't'
            or val == 'on'
            or val == 'ja'
            or tonumber(val) == 1
    then
        return true
    elseif val == false
            or val == 'no'
            or val == 'n'
            or val == 'false'
            or val == 'f'
            or val == 'off'
            or val == 'nein'
            or tonumber(val) == 0
    then
        return false
    else
        return default
    end
end