GNU poke is an interactive, extensible editor for binary data.  Not
limited to editing basic entities such as bits and bytes, it provides
a full-fledged procedural, interactive programming language designed
to describe data structures and to operate on them.

If you are interested in helping in the development, please check out
the source code repository (see https://savannah.gnu.org/git/?group=poke)
and start by reading the file HACKING carefully.
