Record usage enhancements

The .* notation for records in function calls and returns is discouraged.

Genero BDL version 3.20 introduced enhancements for records usage, by avoiding the .* notation when assigning records.

Starting with version 4.00, Genero BDL provides more enhancements for records, with the goal to avoid the .* notation in function calls.

The .* notation for records as function parameters and returns is still supported for backward compatibility. There is no need to change existing code. Use the new syntax without .* in new development.

The improvement discussed here is about using records in function calls and expressions: The .* notation is still required in other instructions such as EXECUTE stmt USING record.*, FETCH cursor INTO record.*, INPUT BY NAME record.*, etc.

The version 4.00 compiler accepts RECORD types in expressions (assignments, function parameters and return values), only if the source and destination types are known and are compatible. To return and assign a record from a function without the .* notation, this implies a user type declared with TYPE type-name, and the RETURNS(type-name) clause in the function definition.

By using the new syntax without .*, records are passed as a single structured value, allowing better compiler checks, to improve overall code readability and robustness.

With Genero BDL 3.20 and methods for types, it is already possible to pass records without the .* notation, as single structured value. Starting with version 4.00, this mechanism is now extended to regular functions:

TYPE t_cust RECORD LIKE customer.*
...
FUNCTION insert_cust(r t_cust) RETURNS ()
    ...
END FUNCTION
...
   DEFINE c t_cust
   CALL insert_cust( c )

Without the .* notation, records are still passed by value, and there is no performance improvement compared to the .* notation. If you need to improve the execution time in functions, pass records by reference with the INOUT keyword.

With Genero BDL 4.00, records returned as a single structured value from functions can be assigned to a target record variable with the exact same type, by using the LET instruction:

TYPE t_cust RECORD LIKE customer.*
...
FUNCTION new_customer() RETURNS (t_cust)
    DEFINE c t_cust
    ...
    RETURN c
END FUNCTION
...
    DEFINE r t_cust
    LET r = new_customer()

Furthermore, Genero BDL version 4.00 allows to use records in expressions, especially when returned from functions. This allows for example to do nested function calls, to pass records back and forth:

TYPE t_cust RECORD LIKE customer.*
...
FUNCTION new_customer() RETURNS (t_cust)
...
FUNCTION update_customer(c t_cust) RETURNS (t_cust)
...
   DEFINE r1 t_cust
   LET r1 = update_customer( new_customer() )

Note that built-in APIs such as base.Channel do also accept simple record names as parameter, without the need to specific the [ ] brackets and .* notation:

DEFINE ch base.Channel
...
CALL ch.write( r_cust )
...
CALL ch.read( r_cust )

For more details, see: Records and functions, Passing records as single structured value, Returning records as single structured value.