parsley_grammar_simple_math_expression_parser.py

1import parsley
2
3# Define the grammar for a simple calculator
4grammar = """
5digit = :d -> int(d)
6number = digit+:ds -> int(''.join(map(str, ds)))
7expr = number:n1 '+' number:n2 -> n1 + n2
8"""
9
10# Create a compiled grammar object
11make_parser = parsley.makeGrammar(grammar, {})
12
13# Use the parser to evaluate an expression
14parser = make_parser("2+2")
15result = parser.expr()
16
17print(result) # Output: 4