calculator

Simple Calculator Expression Parser

This is a simple calculator expression parser that can parse and evaluate arithmetic expressions.

Rules

num: [0-9]+                   # integer
paren_expr: '(' expr ')'      # parenthesized expression
expr0: num | paren_expr       # ^
expr1: expr0 ((*|/) expr0)*   # | Operator precedence
expr2: expr1 ((+|-) expr1)*   # | goes stronger
expr: expr2                   # | as we go up
line_parser: expr lineend
lineend: '\0'

whitespaces: ' ' | '\n'

Source code in src/main.rs