parse(input: &str) -> Expression { let mut tokens = tokenize(input); fn parse_expr<'a>(tokens: &mut Tokenizer<'a>) -> Expression { let Some(tok) = tokens.next() else { panic!("Fim de entrada inesperado"); operação binária, se presente. match tokens.next() { None => expr, Some(Token::Operator(op)) => Expression::Operation( Box::new(expr), op, Box::new(parse_expr(tokens)), ), Some(tok) => panic!("Token inesperado inesperado {tok:?}"), } 185 } parse_expr(&mut tokens) } fn main() { let expr = parse("10+foo+20-30"); println!("{expr:?}"); } 29.7.1 Solução use thiserror::Error; use std::iter::Peekable; use

bison */ %{ #include extern int yylex(void); extern int yyerror(char *); %} /* declare tokens */ %token NUMBER %token OP_ADD OP_SUB OP_MUL OP_RGT OP_LFT OP_EQU %% calc: | calc exp OP_EQU {