kaniblu / yaap

Yet another argument parser (Yaap)

Yet Another Argument Parser (Yaap)

This is a sugar-coated wrapper for python's standard library argparse that improves the library by the following ways.

• Yaap standardizes argument types into int, float, bool, str, path, and the respective list types. If you are interested in having custom types, you may skip this library.

• Yaap allows arguments to be specified using json or yaml configuration files. There are several other libraries that I am aware of that achieves similar effects. argparse itself allows arguments to be listed using line-delimited text file using fromfile_prefix_char option, but the readability is poor. ConfigArgParse also provides similar functionality, but it uses in-house yaml/json parser that works poorly in some cases. Yaap uses standard pyyaml to parse configuration files.

• Yaap offers configuration validation using jsonschema, ensuring integrity of the input configuration file.

Installation

Yaap can be installed from pypi.

$ pip install yaap

Quickstart

Create parsers by filling in intended argument type object into parser.add.

from yaap import *

parser = Yaap()
parser.add(Int(
    "int", shortcut="i", min_bound=0, required=True
))
parser.add(IntList(
    "int-list"
))
parser.add(Float(
    "float", min_bound=-2.0, required=True
))
parser.add(FloatList(
    "float-list", min_bound=2.0, multiples=5.0
))
parser.add(Path(
    "path", must_exist=True, required=True
))
parser.add(Path(
    "dir", must_exist=True, is_dir=True
))
parser.add(Str(
    "str", regex=r"[a-c][0-9]"
))
parser.add(StrList(
    "str-list", min_length=3
))
parser.add(Bool(
    "bool", help="this is a bool"
))

Call parser.parse to perform argument parsing.

args = parser.parse(
    "--int 3 --int-list 2 3 --float 3.0 --float-list 5 10 "
    "--path tests/test.json --dir tests --str b5 "
    "--str-list abc defg --bool".split()
)

The resulting object is a dictionary.

>>> import pprint; pprint.pprint(args)
{'bool': True,
 'dir': '/Users/kani/Clouds/Dropbox/Codes/Python/yaap/tests',
 'float': 3.0,
 'float_list': [5.0, 10.0],
 'int': 3,
 'int_list': [2, 3],
 'path': '/Users/kani/Clouds/Dropbox/Codes/Python/yaap/tests/test.json',
 'str': 'b5',
 'str_list': ['abc', 'defg']}

Resulting arguments can be validated against the parser.

# This will throw `ValidationError` if the validation fails.
parser.validate(args)

License

MIT License