Function parse_unwind_clause

src/cypher/cypher.c:1881–1925

Parse UNWIND [...] AS var clause into query */

/* Parse UNWIND [...] AS var clause into query */
static void parse_unwind_clause(parser_t *p, cbm_query_t *q) {
    advance(p);
    if (check(p, TOK_LBRACKET)) {
        /* Literal list: [1, 2, 3] — collect as JSON array string */
        advance(p);
        char buf[CBM_SZ_2K] = "[";
        int blen = SKIP_ONE;
        /* snprintf returns the length it WOULD have written, so a single
         * oversized token (string literals lex up to CBM_SZ_4K-1) can push
         * blen past sizeof(buf). Clamp after every write and guard the raw
         * buf[blen++] stores, mirroring format_collect_list(). */
        const int cap = (int)sizeof(buf);
        while (!check(p, TOK_RBRACKET) && !check(p, TOK_EOF)) {
            if (blen > SKIP_ONE && blen < cap - SKIP_ONE) {
                buf[blen++] = ',';
            }
            if (check(p, TOK_STRING)) {
                blen += snprintf(buf + blen, (size_t)(cap - blen), "\"%s\"", peek(p)->text);
                advance(p);
            } else if (check(p, TOK_NUMBER)) {
                blen += snprintf(buf + blen, (size_t)(cap - blen), "%s", peek(p)->text);
                advance(p);
            } else {
                advance(p);
            }
            if (blen >= cap) {
                blen = cap - SKIP_ONE;
            }
            match(p, TOK_COMMA);
        }
        expect(p, TOK_RBRACKET);
        if (blen < cap - SKIP_ONE) {
            buf[blen++] = ']';
        }
        buf[blen] = '\0';
        q->unwind_expr = heap_strdup(buf);
    } else if (check(p, TOK_IDENT)) {
        q->unwind_expr = heap_strdup(advance(p)->text);
    }
    expect(p, TOK_AS);
    const cbm_token_t *alias = expect(p, TOK_IDENT);
    if (alias) {
        q->unwind_alias = heap_strdup(alias->text);
    }
}

/* Parse a chain of MATCH / OPTIONAL MATCH patterns into query.
 * Returns -1 on error (fills p->error). */