RESERVED WORDS

See also the Lua reference manual

and    break   do       else   elseif   end
false  for     function goto   if       in
local  nil     not      or     repeat   return
then   true    until    while

You may not use reserved words as variable names. The following names are valid variable-names but are already assigned in standard Lua:

   assert          collectgarbage      dofile
   error           getmetatable        ipairs
   load            loadfile            next
   pairs           pcall               print
   rawequal        rawget              rawlen
   rawset          require             select
   setmetatable    tonumber            tostring
   type            warn                xpcall
   _ENV            _G                  _PROMPT
   _PROMPT2        _VERSION
together with the names of the standard libraries:

   coroutine       debug               io
   os              package             string
   table
To these RiscLua adds libraries:

   lpeg             riscos 

If you assign your own values to them beware that you may lose their initial values.