You can control the input file format by varying certain command-line
arguments, in particular the ‘-t’ option. The input's appearance
is similar to GNU utilities
bison (or UNIX
yacc). Here's an outline of the general
declarations %% keywords %% functions
bison, the declarations section and
the functions section are optional. The following sections describe the
input format for each section.
It is possible to omit the declaration section entirely, if the ‘-t’ option is not given. In this case the input file begins directly with the first keyword line, e.g.:
january february march april ...