if not gtdata_doc_dir then gtdata_doc_dir = "./" end
print ([[

File format for option -regionmapping:

The file supplied to option -regionmapping defines a ``mapping''.  A mapping
maps the sequence-regions given in the GFF3_file to a sequence file containing
the corresponding sequence. Mappings can be defined in one of the following two
forms:
]])
print(io.open(gtdata_doc_dir.."regionmapping_table.lua"):read("*a"))
print([[
or
]])
print(io.open(gtdata_doc_dir.."regionmapping_function.lua"):read("*a"))
print([[
The first form defines a Lua (http://www.lua.org/) table named ``mapping''
which maps each sequence region to the corresponding sequence file.
The second one defines a Lua function ``mapping'', which has to return the
sequence file name when it is called with the sequence_region as argument.]])
