Feature request: Allow reference to previous expression evaluations in debug console

It's often generally useful to be able to refer to the results of an earlier expression when exploring the state of a program. This is related to #281, but different. And possibly possible to implement.

result.getBlob("details")
> JDBCBlobClient (id=108)
result.getBlob("details").toString()
> "org.hsqldb.jdbc.JDBCBlobClient@63611043" (id=111)
Utils.fromJson(result.getBlob("details").getBinaryStream())
> BuildRequest (id=119)

This could be changed to

result.getBlob("details")
> JDBCBlobClient ($id_108)
$id_108.toString()
> "org.hsqldb.jdbc.JDBCBlobClient@63611043" ($id_111)
Utils.fromJson($id_108.getBinaryStream())
> BuildRequest ($id_119)

This would allow exploring the results from calls where repeating the call would return different results, and would also allow use of APIs that require objects as parameters, for example,

new byte[10000]
> byte[10000] ($id_120)
result.getBlob("details").getBinaryStream().read($id_120, 0, 10000)
> 200
new String($id_120)
> "The string result is displayed here..."

从调试控制台入口点开始，检查表达式的求值和显示方式。定义之前的结果如何获得类似 $id_108 的引用，以及这些引用如何传递到后续表达式中；完成标准是结果可以重复使用而无需重复调用，包括作为对象或数组参数使用。