ABAP_to_the_Future

Conditional Logic 2.5
If the functional method in Listing 2.35 returns a string and that string is NO NO!
Do not blow up the world, whatever you do, do not blow up the world, then
the result is NOT INITIAL and thus evaluated as true, and so it is curtains for all of
us.
2.5.3 Using XSDBOOL as a Workaround for BOOLC
Another common situation with respect to Boolean logic (or the lack thereof)
within ABAP is a case in which you want to send a TRUE/FALSE value to a method
or get such a value back from a functional method. In ABAP, you cannot just say
something like the following:
RF_IS_A_MONSTER = ( LD_STRENGTH > 100 AND LD_SANITY < 20)
Although, in some programming language s you can do precisely that (can you
guess which computer could do that in 1981?). Again, we have a workaround in
the form of the built-in function BOOLC (Listing 2.36).
* Postconditions
zcl_dbc=>ensure( id_that = 'A result table is returned'(005)
if_true = boolc( et_return[] IS NOT INITIAL ) ).
Listing 2.36 BOOLC
In Listing 2.36, you pass in a TRUE/FALSE value based on whether an internal table
has any entries. This works fine.
However, what if you want to test for a negative using this method? Say, for
example, that you want to pass in to parameter IF_TRUE a TRUE/FALSE value that’s
true if the table is empty. If yo u use the previous technique using BOOLC, then
things start going horribly wrong. This can be demonstrated by running the code
in Listing 2.37.
DATA: lt_empty TYPE STANDARD TABLE OF ztvc_monsters.
IF boolc( lt_empty[] IS NOT INITIAL ) = abap_false.
WRITE:/ 'This table is empty'.
ELSE.
WRITE:/ 'This table is as full as full can be'.
ENDIF.
IF boolc( 1 = 2 ) = abap_false.
WRITE:/ '1 does not equal 2'.
ELSE.
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