Function parse_where

nodedb/src/engine/graph/pattern/compiler/clauses.rs:10–52

Parse WHERE predicates.

(text: &str)

/// Parse WHERE predicates.
pub(super) fn parse_where(text: &str) -> crate::Result<Vec<WherePredicate>> {
    let trimmed = text.trim();
    if trimmed.is_empty() {
        return Ok(Vec::new());
    }

    let mut predicates = Vec::new();
    let parts = split_by_and(trimmed);

    for part in parts {
        let part = part.trim();
        if part.is_empty() {
            continue;
        }

        let upper_part = part.to_uppercase();

        // NOT EXISTS { MATCH ... }
        if upper_part.starts_with("NOT EXISTS") {
            let brace_start = part.find('{').ok_or_else(|| crate::Error::BadRequest {
                detail: "NOT EXISTS requires { MATCH ... }".to_string(),
            })?;
            let brace_end = part.rfind('}').ok_or_else(|| crate::Error::BadRequest {
                detail: "unclosed '{' in NOT EXISTS".to_string(),
            })?;
            let inner = part[brace_start + 1..brace_end].trim();
            let inner_clauses = parse_match_clauses(inner)?;
            if let Some(clause) = inner_clauses.into_iter().next() {
                predicates.push(WherePredicate::NotExists {
                    sub_pattern: clause,
                });
            }
            continue;
        }

        // Simple comparison: `a.name = 'Alice'` or `a.age > 25`.
        if let Some(pred) = parse_comparison_predicate(part) {
            predicates.push(pred);
        }
    }

    Ok(predicates)
}

/// Parse a comparison predicate: `a.name = 'Alice'`, `a.age > 25`.
fn parse_comparison_predicate(text: &str) -> Option<WherePredicate> {