0 400 400   % SCE_VISUALPROLOG_KEY_MAJOR (1)
 0 400 400   goal
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_KEY_MINOR (2)
 0 400 400   procedure
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_KEY_DIRECTIVE (3)
 0 400 400   #include
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_COMMENT_BLOCK (4)
 0 400 400   /**
 0 400 400      SCE_VISUALPROLOG_COMMENT_KEY (6)
 0 400 400      @detail
 0 400 400      SCE_VISUALPROLOG_COMMENT_KEY_ERROR (7)
 0 400 400      @unknown
 0 400 400    /* SCE_VISUALPROLOG_IDENTIFIER (8)
 0 400 400       SCE_VISUALPROLOG_VARIABLE (9)
 0 400 400       SCE_VISUALPROLOG_ANONYMOUS (10)
 0 400 400       SCE_VISUALPROLOG_NUMBER (11)
 0 400 400       SCE_VISUALPROLOG_OPERATOR (12) */ */
 0 400 400   singleton -->
 0 400 400       [S],
 2 400 401 +     {
 0 401 401 |         string_lower(S, L),
 0 401 401 |         atom_codes(L, Bytes),
 0 401 401 |         sort(0, @=<, Bytes, [95, _discard])
 0 401 400 |     }.
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_COMMENT_LINE (5)
 0 400 400   % @detail
 0 400 400   % @unknown
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_STRING (16)
 0 400 400   "string"
 0 400 400   'string'
 0 400 400   % ISO Prolog back-quoted string
 0 400 400   `string`
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_STRING_ESCAPE (17)
 0 400 400   "\n"
 0 400 400   '\uAB12'
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_STRING_ESCAPE_ERROR (18)
 0 400 400   "\ "
 0 400 400   
 0 400 400   % SCE_VISUALPROLOG_STRING_EOL_OPEN (19)
 0 400 400   "open string
 0 400 400   
 0 400 400   % Not implemented for ISO/SWI-Prolog:
 0 400 400   % SCE_VISUALPROLOG_STRING_VERBATIM
 0 400 400   % SCE_VISUALPROLOG_STRING_VERBATIM_SPECIAL
 0 400 400   % SCE_VISUALPROLOG_STRING_VERBATIM_EOL
 0 400 400   @"verbatim string"
 0 400 400   @"""special"" verbatim string"
 0 400 400   @"multi-line
 0 400 400     verbatim
 0 400 400     string"
 1 400 400