Function parse

nodedb-sql/src/ddl_ast/parse/dispatch.rs:21–93

Try to parse a DDL statement from raw SQL. Returns `None` for non-DDL queries (SELECT, INSERT, etc.) that should flow through the normal planner. Returns `Some(Err(...))` when the SQL is structurally a DDL command but contains a reserved identifier that would be misrouted by the dispatcher.

(sql: &str)

/// is structurally a DDL command but contains a reserved identifier that
/// would be misrouted by the dispatcher.
pub fn parse(sql: &str) -> Option<Result<NodedbStatement, SqlError>> {
    let trimmed = sql.trim();
    if trimmed.is_empty() {
        return None;
    }
    let upper = trimmed.to_uppercase();
    let parts: Vec<&str> = trimmed.split_whitespace().collect();
    if parts.is_empty() {
        return None;
    }

    // Graph DSL (`GRAPH ...`, `MATCH ...`, `OPTIONAL MATCH ...`) has its own
    // tokenising parser — delegate early using token-aware dispatch so that
    // leading block/line comments and quoted values containing DSL keywords
    // are never mistakenly matched.
    let first = lex::first_sql_word(trimmed).map(|w| w.to_uppercase());
    let is_graph = match first.as_deref() {
        Some("GRAPH") | Some("MATCH") => true,
        Some("OPTIONAL") => lex::second_sql_word(trimmed)
            .map(|w| w.eq_ignore_ascii_case("MATCH"))
            .unwrap_or(false),
        _ => false,
    };
    if is_graph {
        return graph_parse::try_parse(trimmed).map(Ok);
    }

    // Dispatch by family. Order matters only where prefixes overlap
    // (e.g. DESCRIBE vs DESCRIBE SEQUENCE — handled inside each
    // family's `try_parse`). A `Some(Err(...))` from any family
    // short-circuits the chain — reserved-identifier errors must not
    // be silently swallowed by the next family's `None` path.
    macro_rules! try_family {
        ($result:expr) => {{
            let r = $result;
            if r.is_some() {
                return r;
            }
        }};
    }

    // `SHOW GRAPH STATS` must be checked before the generic collection parser
    // so its `SHOW` prefix is not consumed by `SHOW COLLECTIONS`/etc.
    try_family!(graph_stats::try_parse(&upper, &parts, trimmed));
    // Conflict policy must be checked before the generic collection parser
    // so "SET ON CONFLICT" does not fall through to the raw-SQL path.
    try_family!(conflict_policy::try_parse(&upper, &parts, trimmed));
    try_family!(collection::try_parse(&upper, &parts, trimmed));
    try_family!(index::try_parse(&upper, &parts, trimmed));
    try_family!(trigger::try_parse(&upper, &parts, trimmed));
    try_family!(schedule::try_parse(&upper, &parts, trimmed));
    try_family!(sequence::try_parse(&upper, &parts, trimmed));
    try_family!(alert::try_parse(&upper, &parts, trimmed));
    try_family!(retention::try_parse(&upper, &parts, trimmed));
    try_family!(cluster_admin::try_parse(&upper, &parts, trimmed));
    try_family!(maintenance::try_parse(&upper, &parts, trimmed));
    try_family!(backup::try_parse(&upper, &parts, trimmed));
    // COPY FROM file-path form — must come after backup so STDIN forms fall through.