kartynnik

#!/usr/bin/env python3
"""Demonstrates parsing of bracket expressions via recursive descent.

The formal grammar is as follows (notice the lack of left recursion):
    S := '(' S ')' S | '[' S ']' S | '{' S '}' S | '<' S '>' S | ''
Observe how `parse_expression` follows this definition.
"""
import enum
from typing import Iterable, Tuple