type HintRecord struct {
	Key   *Ident
	Value Expr
}

@{ hint [, ...] }

hint:
  [engine_name.]hint_name = value

spanner> @{spanner.optimizer_version=5} SELECT 1;
+-------+
|       |
| INT64 |
+-------+
| 1     |
+-------+
1 rows in set (1.02 msecs)
timestamp:            2024-12-23T23:55:34.448052+09:00
cpu time:             0.98 msecs
rows scanned:         0 rows
deleted rows scanned: 0 rows
optimizer version:    5
optimizer statistics: auto_20241222_02_16_49UTC

$ go run github.com/cloudspannerecosystem/memefish/tools/parse@latest --mode query "@{spanner_emulator.disable_query_partitionability_check=true} SELECT * FROM Singers ORDER BY FirstName" 
--- Error
syntax error: :1:19: expected token: =, but: .
  1|  @{spanner_emulator.disable_query_partitionability_check=true} SELECT * FROM Singers ORDER BY FirstName
   |                    ^