Module enthought.​ets.​argparse

Command-line parsing library

This module is an optparse-inspired command-line parsing library that:

• handles both optional and positional arguments
• produces highly informative usage messages
• supports parsers that dispatch to sub-parsers

The following is a simple usage example that sums integers from the command-line and writes the result to a file:

parser = argparse.ArgumentParser(
    description='sum the integers at the command line')
parser.add_argument(
    'integers', metavar='int', nargs='+', type=int,
    help='an integer to be summed')
parser.add_argument(
    '--log', default=sys.stdout, type=argparse.FileType('w'),
    help='the file where the sum should be written')
args = parser.parse_args()
args.log.write('%s' % sum(args.integers))
args.log.close()

The module contains the following public classes:

ArgumentParser

The main entry point for command-line parsing. As the example above shows, the add_argument() method is used to populate the parser with actions for optional and positional arguments. Then the parse_args() method is invoked to convert the args at the command-line into an object with attributes.

ArgumentError

The exception raised by ArgumentParser objects when there are errors with the parser's actions. Errors raised while parsing the command-line are caught by ArgumentParser and emitted as command-line messages.

FileType

A factory for defining types of files to be created. As the example above shows, instances of FileType are typically passed as the type= argument of add_argument() calls.

Action

The base class for parser actions. Typically actions are selected by passing strings like 'store_true' or 'append_const' to the action= argument of add_argument(). However, for greater customization of ArgumentParser actions, subclasses of Action may be defined and passed as the action= argument.

HelpFormatter, RawDescriptionHelpFormatter

Formatter classes which may be passed as the formatter_class= argument to the ArgumentParser constructor. HelpFormatter is the default, while RawDescriptionHelpFormatter tells the parser not to perform any line-wrapping on description text.

All other classes in this module are considered implementation details. (Also note that HelpFormatter and RawDescriptionHelpFormatter are only considered public as object names -- the API of the formatter objects is still considered an implementation detail.)