argcompile

ArgCompile

Command-line parsing library

This module proposes to extend argparse command-line parsing library objects in order to promote devices to easily apply post-parsing processing over supplied arguments.

The package contains three public design classes, some useful implementations of them and other auxiliary classes. The most significant ones are described bellow:

ArgumentCompiler

The main entry point for command-line parsing, extended to process new-design group usage test, attribute formation and Namespace compilation. Following its superclass, ArgumentParser, it's filled by Actions that defines as command line should be parsed. By extension, add_attribute() method process the inclusion of complex ActionsContainer named accordingly.

• FileSelector: A multiple file opener that filters selection based on path, filename(s) and extension(s)
• FileComputer: A FileSelector specialization that also defines an output target
• YamlCompuler: A FileComputer based class that restricts yaml and yml file extensions, already loading its content to a dictionary

Attribute

An ActionsContainer specialization to manage parsing of multiple arguments into an unique Namespace attribute. Implementations of it can be made in order to define how a Namespace attribute should be constructed based on the several target arguments parsed.

• Target: Defines a reference collection of the main parsed object
• Extension: Designed to accumulate a list of extensions, allowing defining special arguments for desired options
• Output: Defines title and opening-mode of a writing file

CustomGroup

A group-type class that allows post parsing usage tests to be executed. This design enables the implementation of custom rules in Action groups.

• RequiredGroup: A simple group that checks the presence of its arguments to require at least one has been provided
• DependentGroup: Restricts the use of its arguments based on presence of its dependence list

Example

The following code is a Python program that prints out the file list of a target path

# ls.py
from argcompile import FileSelector

class Ls(FileSelector):
	def __call__(self, namespace):
		for file in namespace.file:
			print(file.name)

compiler = Ls(
	path={
		'*': ['path'],
		'nargs': 1
	}
)
compiler.parse_args()

It can be run at the command line and provides useful help messages:

$ python3 ls.py -h
usage: ls.py [-h] [--all] [-e ext [ext ...]]
           path [filename [filename ...]]

positional arguments:
  path                  define path to look up files from
  filename              define chosen filenames

optional arguments:
  -h, --help            show this help message and exit
  --all                 select all filenames
  -e ext [ext ...],     restrict files extension(s)

When run with the appropriate arguments, it does the job:

$ python3 ls.py . --all
./.gitignore
./DESCRIPTION.md
./LICENSE
./makefile
./MANIFEST.in
./README.md
./setup.cfg
./setup.py