Function parse_condition_expr

src/cypher/cypher.c:1010–1099

}

static cbm_expr_t *parse_condition_expr(parser_t *p) {
    /* Check for NOT prefix at condition level (e.g. NOT n.name CONTAINS "x") */
    bool negated = match(p, TOK_NOT);

    /* EXISTS { pattern } predicate (anchored single-hop existence). */
    if (check(p, TOK_EXISTS)) {
        return parse_exists_predicate(p, negated);
    }

    const cbm_token_t *var = expect(p, TOK_IDENT);
    if (!var) {
        return NULL;
    }

    cbm_condition_t c = {0};
    c.negated = negated;

    /* Label test: WHERE n:Label (openCypher, #241). Modelled as a leaf with
     * op="HAS_LABEL" and value=Label, evaluated against the bound node's label. */
    if (check(p, TOK_COLON)) {
        advance(p);
        const cbm_token_t *lbl = expect(p, TOK_IDENT);
        if (!lbl) {
            return NULL;
        }
        c.variable = heap_strdup(var->text);
        c.op = heap_strdup("HAS_LABEL");
        c.value = heap_strdup(lbl->text);
        return expr_leaf(c);
    }

    if (match(p, TOK_DOT)) {
        const cbm_token_t *prop = expect(p, TOK_IDENT);
        if (!prop) {
            return NULL;
        }
        c.variable = heap_strdup(var->text);
        c.property = heap_strdup(prop->text);
    } else {
        /* No dot: bare alias (e.g. post-WITH variable like "cnt") */
        c.variable = heap_strdup(var->text);
        c.property = NULL;
    }

    /* IS NULL / IS NOT NULL */
    if (check(p, TOK_IS)) {
        advance(p);
        if (match(p, TOK_NOT)) {
            c.op = heap_strdup("IS NOT NULL");
            expect(p, TOK_NULL_KW);
        } else {
            expect(p, TOK_NULL_KW);
            c.op = heap_strdup("IS NULL");
        }
        return expr_leaf(c);
    }

    /* IN [...] */