Function parse_union_except

graphlite/src/ast/parser.rs:464–501

Parse UNION and EXCEPT operations (lower precedence)

(tokens: &[Token])

/// Parse UNION and EXCEPT operations (lower precedence)
fn parse_union_except(tokens: &[Token]) -> IResult<&[Token], Query> {
    let (mut remaining, mut left) = parse_intersect(tokens)?;

    while let Ok((new_remaining, (operation, right))) = parse_union_except_op(remaining) {
        left = Query::SetOperation(SetOperation {
            left: Box::new(left),
            operation,
            right: Box::new(right),
            limit_clause: None,
            order_clause: None,
            location: Location::default(),
        });
        remaining = new_remaining;
    }

    // Check for incomplete set operations (UNION/EXCEPT without right-hand side)
    if !remaining.is_empty() {
        if let Some(token) = remaining.first() {
            match token {
                Token::Union => {
                    return Err(nom::Err::Error(nom::error::Error::new(
                        remaining,
                        nom::error::ErrorKind::Alt,
                    )));
                }
                Token::Except => {
                    return Err(nom::Err::Error(nom::error::Error::new(
                        remaining,
                        nom::error::ErrorKind::Alt,
                    )));
                }
                _ => {}
            }
        }
    }

    Ok((remaining, left))
}

/// Parse INTERSECT operations (higher precedence)
fn parse_intersect(tokens: &[Token]) -> IResult<&[Token], Query> {