Actually, my another proposal is to have true and false as part of the language, where true=1 and false 0 or similar for booleans.

Isn't that the case now?

set true="1",
    false=0,
    j={"a":true,"b":false,"c":(true),"d":(false)}

set iter = j.%GetIterator()
while iter.%GetNext(.key, .value, .type ) {
  write "key = "_key_", value = "_value_", type = "_type,!
}

Output:
key = a, value = 1, type = boolean
key = b, value = 0, type = boolean
key = c, value = 1, type = string
key = d, value = 0, type = number

@Evgeny Shvarov

Unfortunately, I have not yet found a documented and [Not Internal] way out of the box to see not only the text of the request, but also the values of its input parameters.

PS: take a look at the methods of the %SYSTEM.SQL.xDBC class.
Here is an example of the log for the query above (from DbVisualizer):

        SQL text (raw from client): 1 lines
        line 1: SELECT * FROM del . a WHERE id < :%qpar(1)
        Var Types: Parameter 1: Constant of type INTEGER
        INPUT params:
          %qpar(1) = 3

If auditing is enabled, you can see the query without the actual parameter values.
To copy the query to the SQL query tool, the query will also have to be cleaned of garbage.

For example, there is the following query

select * from del.a where id<3

From SMP:

Event: DynamicStatementQuery
Event Data: SELECT * FROM del . a WHERE id < ?

From DbVisualizer:

Event: XDBCStatementQuery
Event Data: SELECT * INTO :i%%col1, :i%%col2, :i%%col3 FROM del . a WHERE id < :%qpar(1)