Options

Option arguments start with a minus or a plus sign, followed by one or more option letters. If a minus sign is used, the options are set. With a plus sign, the options are reset. By default, no options are set. Options can also be set or reset from the LATEX file (see below). This overrides the corresponding options setting from the command line. The effect of setting each option is described below.

-a
An alternate layout is used for the * operator with an empty second argument. Instead of transforming x * into () | x + it is transformed into () + x.
-c
The input is checked for undefined identifiers and unnamed rules. Statistics about those are printed to the standard output stream.
-d
Turns on yacc debugging output. This only works if the program has been compiled with YYDEBUG defined (which is the default) and your yacc supports it.
-i
Index entries are generated for all named rules, i.e., rules that are of the form
-t
Print the parse tree of a rule body as comments in the .rao file.
Options can be set from a LATEX file by use of where options is a set of option arguments just like those allowed on the command line. Options specified this way override those on the command line. The option settings take effect immediately.

Setting options this way is especially useful for the -a, -c and -t options. Messages about redefined identifiers are printed according to the setting of -c in effect at that point, but messages about undefined identifiers and unnamed rules are printed only if -c is still in effect at the end of the input file.