Simple Lexer/Parser for <expr> Grammar 🪄 The grammar rules are as follows: <assign> -> <id> = <expr> <expr> -> <term> {+ <term>} <term> -> <factor> {* <factor>} <factor> -> ( <expr> ) | <id> | <num> <id> -> a | b | c | ... | z <num> -> 0 | 1 | 2 | ...