parser.py

from lark import Lark
import time

clock = time.perf_counter()
with open("whatsapp_grammar.lark") as f:
    GRAMMAR = f.read()

parser = Lark(GRAMMAR, lexer="dynamic_complete")
with open("input_file")as f:
    print(parser.parse(f.read()).pretty())
print("{:.2f} seconds".format(time.perf_counter() - clock))