3.1 Input Format to gperf

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 flex and bison (or UNIX utilities lex and yacc). Here's an outline of the general format:

     declarations
     %%
     keywords
     %%
     functions

Unlike flex or bison, the declarations section and the functions section are optional. The following sections describe the input format for each section.

• Declarations: Declarations.
• Keywords: Format for Keyword Entries.
• Functions: Including Additional C Functions.
• Controls for GNU indent: Where to place directives for GNU indent.

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
     ...