printing.py

'''
Default dataclass printing module doesn't support nested printout and default values.
We use custom solution kindly borrowed from
https://stackify.dev/159839-pretty-print-dataclasses-prettier
'''

from collections.abc import Mapping, Iterable
from dataclasses import is_dataclass, fields


def pretty_print(obj, indent=4):
    """
    Pretty prints a (possibly deeply-nested) dataclass.
    Each new block will be indented by `indent` spaces (default is 4).
    """
    print(stringify(obj, indent))


def stringify(obj, indent=4, _indents=0):
    if isinstance(obj, str):
        return f"'{obj}'"

    if not is_dataclass(obj) and not isinstance(obj, (Mapping, Iterable)):
        return str(obj)

    this_indent = indent * _indents * ' '
    next_indent = indent * (_indents + 1) * ' '
    start, end = f'{type(obj).__name__}(', ')'  # dicts, lists, and tuples will re-assign this

    if is_dataclass(obj):
        body = '\n'.join(f'{next_indent}{field.name}='
                         f'{stringify(getattr(obj, field.name), indent, _indents + 1)},' for field in fields(obj))

    elif isinstance(obj, Mapping):
        if isinstance(obj, dict):
            start, end = '{}'

        body = '\n'.join(f'{next_indent}{stringify(key, indent, _indents + 1)}: '
                         f'{stringify(value, indent, _indents + 1)},' for key, value in obj.items())

    else:  # is Iterable
        if isinstance(obj, list):
            start, end = '[]'
        elif isinstance(obj, tuple):
            start = '('

        body = '\n'.join(f'{next_indent}{stringify(item, indent, _indents + 1)},' for item in obj)

    return f'{start}\n{body}\n{this_indent}{end}'