nested-argparse 0.1.0

A python module that extends argparser to create nested namespace trees for subparsers.

nested-argparse 💬 → 🅰.🅱.🆒

nested-argparse is a python module that non-invasively builds on top of the built-in argparse library to allow subparsers to parse into their own nested namespaces.

The library exposes a class NestedArgumentParser which allows arbitrary nesting without worry of namespace conflicts. This is achieved with the following principles of this library:

• Inversion of Control: A parser, when adding a subparser, is in control of what name to use for the sub-namespace which the subparser sends its parsed args to.
• Drop-In Replacement: The constructor for nested_argparse.NestedArgumentParser can be substituted in directly to where the constructor for argparse.ArgumentParser is being used. All subsequent method calls and subparser API calls should work without any additional code change!
• Customizeability: There are additional kwargs exposed to further customize the nesting options to your liking, if the defaults do not suit your scenario.

The main difference between this library and its built-in counterpart is the return value of the parse_args method. Instead of a flat namespace containing all parsed arguments across all subparsers, NestedArgumentParser will produce a namespace tree.

Quick Example

Given the following parser:

Root Parser with prog='root'
 ├─ positional_1
 ├─ --optional_1
 ├─ --optional_2
 └─ sub parsers with dest='subcommand'
     ├─ Sub Parser 1 with name='sub1'
     │   ├─ --optional_1
     │   └─ --optional_2 with dest='optional2AltName'
     └─ Sub Parser 2 with name='sub2'
         ├─ --optional_1
         └─ --optional_2

And the following args to parse:

Alice --optional_1=Bob sub1 --optional_1=Carol --optional_2=David

The built-in ArgumentParser would not be able to handle the duplication in dests, but NestedArgumentParser will produce the following result when run through parse_args:

Namespace(
  root=Namespace(
    subcommand='sub1',
    positional_1='Alice',
    optional_1='Bob',
    sub1=Namespace(
      optional_1='Carol',
      optional2AltName='David'
    )
  )
)