m-o

A command line tool for parsing Python dataclass reprs and pretty-printing them. The name is based on the WALL-E character M-O, a robot who liked to clean things up.

Installation

shell $ cargo install m-o

Example

```python

my_data.py

@dataclass class Dog: name: str age: int friends: List[str]

pip = Dog("Pip", 7, ["Quincy", "Digger"]) print(pip) ```

```shell $ # without m-o: $ python my_data.py Dog(name="Pip", age=7, friends=["Quincy", "Digger"])

$ # with m-o: $ python my_data.py | m-o --columns 20 Dog( name="Pip", age=7, friends=[ "Quincy", "Digger", ], ) ```

CLI Options

``` USAGE: m-o [OPTIONS]

FLAGS: -h, --help Prints help information -V, --version Prints version information

OPTIONS: -c, --columns Specifies the width of the terminal or file that the results will be printed to. If unspecified, m-o will try to use the width of the current terminal window. Defaults to 80 columns. -i, --indent The number of spaces used for a single indentation in the output. [default: 4] ```

Motivation

Python's pprint.pprint function allows common values (tuples, lists, dicts, etc.) to be pretty-printed, but does not know how to format Python 3.7's dataclasses. I use dataclasses pretty frequently, and often need to debug deeply nested trees of dataclasses. The __repr__ method on dataclasses displays everything on one line which is difficult to read.

Rather than implementing pprint.pprint for your dataclasses (who even knows how to do this anyway?), just print out the value and pipe it into this tool. The data structure will be pretty-printed to your terminal.

(Planned/Current) Features