The second input file format section contains lines of keywords and any associated attributes you might supply. A line beginning with ‘#’ in the first column is considered a comment. Everything following the ‘#’ is ignored, up to and including the following newline. A line beginning with ‘%’ in the first column is an option declaration and must not occur within the keywords section.
The first field of each non-comment line is always the keyword itself. It
can be given in two ways: as a simple name, i.e., without surrounding
string quotation marks, or as a string enclosed in double-quotes, in
C syntax, possibly with backslash escapes like
\xa8. In either case, it must start right at the beginning
of the line, without leading whitespace.
In this context, a “field” is considered to extend up to, but
not include, the first blank, comma, or newline. Here is a simple
example taken from a partial list of C reserved words:
# These are a few C reserved words, see the c.gperf file # for a complete list of ANSI C reserved words. unsigned sizeof switch signed if default for while return
Note that unlike
bison the first ‘%%’ marker
may be elided if the declaration section is empty.
Additional fields may optionally follow the leading keyword. Fields
should be separated by commas, and terminate at the end of line. What
these fields mean is entirely up to you; they are used to initialize the
elements of the user-defined
struct provided by you in the
declaration section. If the ‘-t’ option (or, equivalently, the
‘%struct-type’ declaration) is not enabled
these fields are simply ignored. All previous examples except the last
one contain keyword attributes.