Module:Yesno

local p = {}

function p.yesno(frame)

    -- defaults
    local retvals = {
        yes   = "yes",
        no    = "",
        ["¬"] = ""
    }

    -- Allow arguments to override defaults. Arguments are taken from
    -- the parent frame; other arguments are ignored.
    local args;
    if frame == mw.getCurrentFrame() then
        -- We're being called via #invoke. If the invoking template passed any args, use
        -- them. Otherwise, use the args that were passed into the template.
        args = frame:getParent().args;
        for k, v in pairs(frame.args) do
            args = frame.args;
            break
        end
    else
        -- We're being called from another module or from the debug console, so assume
        -- the args are passed in directly.
        args = frame;
    end
    
    for k,v in pairs(args) do
        retvals[k] = v
    end

    val = args[1]

    -- First deal with the case if val is nil, then deal with other cases.
    if val == nil then
        return retvals['¬']
    end

    val = val:lower()          -- Make lowercase.
    val = val:match'^%s*(.*%S)' or ''  -- Trim whitespace.

    if val == '' then
        return retvals['blank'] or retvals['no']
    elseif val == 'n' or val == 'no'  or tonumber(val) == 0 then
        return retvals['no']
    elseif val == 'y' or val == 'yes' or tonumber(val) == 1 then
        return retvals['yes']
    elseif val == '¬' then
        return retvals['¬']
    else
        return retvals['def'] or retvals['yes']
    end
end

return p