meta_printer.py

import inspect
from operator import itemgetter


def var_name(var, *, ignore_underscore: bool = True, fix: bool = True):
    """ Find all the variable names in caller's parent scope whos value is 'var'
    
    Example
    -------
    >>> def meta_printer(var):
    ...     print(f"{var_name(var)} = {var}")
    
    >>> params = dict(hello=1, sailor=True)
    >>> meta_printer(params)
    params = {'hello': 1, 'sailor': True}
    >>> meta_printer('hello')
    var = hello
    """

    callers_parent_scope = inspect.currentframe().f_back.f_back.f_locals.items()
    filter_ = lambda e: e[1] is var and not (ignore_underscore and e[0].startswith("_"))
    names_from_scope = lambda scope: list(map(itemgetter(0), filter(filter_, scope)))
    names = names_from_scope(callers_parent_scope)

    # If more than one name is found and 'fix' is enabled, attempt to fix with
    # the name of variable passed to *this* function (as opposed to the caller).
    if fix:
        if len(names) != 1:
            parent_scope = inspect.currentframe().f_back.f_locals.items()
            names = names_from_scope(parent_scope)
            names = [""] if len(names) != 1 else names  # Fall back to empty string
        names = names[0]

    return names


def meta_printer(var: Any):
    """ Prints the name and value of the variable"""
    print(f"{var_name(var)} = {var}")


if __name__ == "__main__":
    params = dict(hello=1, sailor=True)

    meta_printer(params)
    meta_printer('hello')

    # This is already a feature in Python 3.8
    # https://docs.python.org/3/whatsnew/3.8.html#f-strings-support-for-self-documenting-expressions-and-debugging
    import sys
    if sys.version_info > (3, 8):
        print(f"{params = }")
        print(f"{'hello' = }")