This function is used to create an instance of a parser object
which when combined with the parse_args
, make_option
, and add_option
methods is very useful for parsing options from the command line.
OptionParser(usage = "usage: %prog [options]", option_list = list(),
add_help_option = TRUE, prog = NULL, description = "",
epilogue = "")
The program usage message that will printed out if
parse_args
finds a help option, %prog
is substituted with the
value of the prog
argument.
A list of of OptionParserOption
instances that will
define how parse_args
reacts to command line options.
OptionParserOption
instances are usually created by make_option
and can also be added to an existing OptionParser
instance via the
add_option
function.
Whether a standard help option should be automatically
added to the OptionParser
instance.
Program name to be substituted for %prog
in the usage
message (including description and epilogue if present),
the default is to use the actual Rscript file name if called by an
Rscript file and otherwise keep %prog
.
Additional text for print_help
to print out between
usage statement and options statement
Additional text for print_help
to print out after
the options statement
An instance of the OptionParser
class.
Python's optparse
library, which inspired this package,
is described here: http://docs.python.org/library/optparse.html