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