Convert dynamic REF TO DATA structure to static - dynamic

Question

I created structure with three components, one of which is type ref to data and a table type of this structure. The problem is, how do I add data to this table?
It always has three components, but only one of them is discovered during processing, I always know two of them. Thus I always use the entire table type ref to data and then determine the type of this structure and create the table on it.
The issue here is that by doing this, even though I know two of the components, the whole itab will be dynamic, so I must use it in methods exporting/importing a type ref to data, which is inconvenient.
The method below will always return a table type ref to data, which is completely dynamic (type ref to data), but the structure of the table will always be like this:
component 1 -> type pc261.
component 2 -> type pay99_international.
compoment 3 -> well this is always a mistery hehe
methods get_payroll
importing it_rgdir type hrpy_tt_rgdir
returning value(rt_value) type ref to data.
method get_payroll.
field-symbols: <lt_payroll> type standard table.
create data rt_value type standard table of (mv_py_struct_type).
assign rt_value->* to <lt_payroll>.
...
endmethod.
My intention was to have the returning value with another type, a known type, with which I can use the two known components more easily. The idea I had was to create a type with only the unknown field as ref to data, than have a table of it.
This way, I would be able to use it inside methods without having to work so "dynamicaly", which altough works perfectly, is kind of difficult to understand only by reading the code.
types begin of gty_s_generic_payroll.
types evp type pc261.
types inter type pay99_international.
types nat type ref to data.
types end of gty_s_generic_payroll.
types gty_t_generic_payroll type table of gty_s_generic_payroll.
The problem is, how to use an itab of type gty_t_generic_payroll as declared above?
I must somehow create the component 3, but I have no idea how to do it...
At the end, I have a generic field-symbol, that is type table, that has the two known components + the third one that was discovered during processing time.
So how can I pass the content of this field symbol to a table type gty_t_generic_payroll?
data lt_payroll type ref to data.
field-symbols <lt_payroll> type any table.
lt_payroll = mo_payroll->get_payroll( lt_rgdir ). "this will return type ref to data
assign lt_payroll->* to <lt_payroll>.
After executing this code <lt_payroll> has all the values, but it is a dynamic table where I cannot use components <lt_payroll>[1]-inter.
So how to pass to gty_t_generic_payroll-typed variable, so that I can access components without much dynamics?

Answer 1

Given your target structure and table like this:
TYPES:
BEGIN OF payroll_row_type,
known_first_component TYPE something_we_know,
known_second_component TYPE something_else_we_know,
discovered_component TYPE REF TO data,
END OF payroll_row_type.
TYPES payroll_table_type TYPE STANDARD TABLE OF payroll_row WITH EMPTY KEY.
If you now have another table, whose type at runtime is:
TYPES:
BEGIN OF discovered_row_type,
known_first_component TYPE something_we_know,
known_second_component TYPE something_else_we_know,
known_third_component TYPE some_data_type,
END OF discovered_row_type.
TYPES discovered_table_type TYPE STANDARD TABLE OF discovered_row WITH EMPTY KEY.
You can move one to the other with
DATA source TYPE discovered_table_type.
DATA target TYPE payroll_table_type.
DATA resolved_component TYPE REF TO DATA.
DATA(descriptor) =
cl_abap_elemdescr=>describe_by_data( source_row-known_third_component ).
LOOP AT source INTO DATA(source_row).
DATA(target_row) =
VALUE payroll_row_type(
known_first_component = source_row-known_first_component
known_second_component = source_row-known_second_component ).
CREATE DATA target_row-discovered_component TYPE descriptor.
ASSIGN source_row-known_third_component TO FIELD-SYMBOL(<source_component>).
ASSIGN target_row-discovered_component TO FIELD-SYMBOL(<target_component>).
<target_component> = <source_component>.
INSERT target_row INTO TABLE target.
ENDLOOP.

Answer 2

The question and answers may look confusing for future visitors (what is the actual question?), so here is my two cents.
Summary of the question :
You call an external code (1) which gives you an internal table generated dynamically, but you know that all the components are always the same except one which varies but is at the same position, so you'd like to refer to its components statically, except for the one which varies.
(1) so, you can't adapt it.
Your workaround is to define an equivalent internal table statically and the component which varies will be defined as a data reference type (pointer to any data object), then to initialize it by copying the data from the dynamic internal table.
You ask for another better solution because yours consumes extra memory (two internal tables) and decreases the performance (copy process).
Answer :
No better solution

Answer 3

It looks like I was able to pass the values from the fully generic table (type ref to data) to another table that is 1/3 generic (type gty_t_generic_payroll):
methods get_payroll
importing it_rgdir type hrpy_tt_rgdir
returning value(rt_value) type gty_t_generic_payroll.
method get_payroll.
data lt_payroll type gty_t_generic_payroll.
data lt_payroll_aux type ref to data.
field-symbols: <lt_payroll_aux> type standard table.
create data lt_payroll_aux type standard table of (mv_py_struct_type).
assign lt_payroll_aux->* to <lt_payroll_aux> .
call function ' '.
call function ' '
exporting
= mv_relid
= mv_pernr
= xsdbool( gs_parm-use_natio <> abap_true )
tables
= it_rgdir
= <lt_payroll_aux> "table with the values I need
exceptions
= 0.
if sy-subrc <> 0.
return.
endif.
loop at <lt_payroll_aux> assigning field-symbol(<ls_payroll_aux>).
assign component 1 of structure <ls_payroll_aux> to field-symbol(<evp>).
assign component 2 of structure <ls_payroll_aux> to field-symbol(<inter>).
assign component 3 of structure <ls_payroll_aux> to field-symbol(<nat>).
data(ls_value) = value gty_s_generic_payroll(
evp = <evp>
inter = <inter>
).
get reference of <nat> into ls_value-nat.
append ls_value to rt_value. "returning table, with values I need and
"now with 2/3 known types
endloop.
endmethod.
At the end of the day, I acomplished what I needed, but unfortunately I do loose a lot of performance, since I must loop twice in the results now.
to populate the not-so-dynamic-table
to do the actual process of the report (at least it gets pretier lol)
This is the only way because I can't simply use insert lines of dynamic_itab to not_so_dynamic_itab, since the third component is reference .