Function tokenize

nodedb/src/control/security/predicate_parser.rs:53–133

(input: &str)

// ── Tokenizer ───────────────────────────────────────────────────────────

fn tokenize(input: &str) -> Result<Vec<String>, PredicateParseError> {
    let mut tokens = Vec::new();
    let mut chars = input.chars().peekable();

    while let Some(&ch) = chars.peek() {
        if ch.is_whitespace() {
            chars.next();
            continue;
        }

        if ch == '(' || ch == ')' {
            tokens.push(ch.to_string());
            chars.next();
            continue;
        }

        // Quoted string literal.
        if ch == '\'' {
            chars.next(); // consume opening quote
            let mut s = String::new();
            loop {
                match chars.next() {
                    Some('\'') => {
                        // Check for escaped quote ('')
                        if chars.peek() == Some(&'\'') {
                            s.push('\'');
                            chars.next();
                        } else {
                            break;
                        }
                    }
                    Some(c) => s.push(c),
                    None => {
                        return Err(PredicateParseError::InvalidLiteral(
                            "unterminated string".into(),
                        ));
                    }
                }
            }
            tokens.push(format!("'{s}'"));
            continue;
        }

        // Operators: =, !=, <>, <, <=, >, >=
        if matches!(ch, '=' | '!' | '<' | '>') {
            let mut op = String::new();
            op.push(ch);
            chars.next();
            if let Some(&next) = chars.peek()
                && ((ch == '!' && next == '=')
                    || (ch == '<' && matches!(next, '=' | '>'))
                    || (ch == '>' && next == '='))
            {
                op.push(next);
                chars.next();
            }
            tokens.push(op);
            continue;