10.7 Validation Subroutines
Some programmers like to code validation logic into subroutines, and do not easily accept the LANSA approach of:
request <<data>>
begincheck
<<validate>>
endcheck
Unable to resist the urge to use a subroutine they soon change the program to be like this:
dountil #errors = n
request <<data>>
execute validate
enduntil
subroutine validate
begincheck
<<validate>>
if_error
change #errors Y
else
change #errors N
endif
endcheck
endroutine
and are surprised when the whole program aborts
The reason is that the ENDCHECK command, by default, returns control to the last display (if it can be found in same routine), otherwise it aborts the program.
In this subroutine the ENDCHECK command has no last display to return control to, so it aborts. If you must code validation routines, the best structure is probably something like the following:
dountil #errors = 0
request <<data>>
execute validate
enduntil
subroutine validate
change #errors 0
begincheck keep_count(#errors)
<<validate>>
endcheck if_error(*next)
endroutine