Prefer basis checks to regular expressions

CALL FUNCTION 'SEO_CLIF_CHECK_NAME'
  EXPORTING
    cls_name = class_name
  EXCEPTIONS
    ...

instead of reinventing things

" anti-pattern
DATA(is_valid) = matches( val     = class_name
                          pattern = '[A-Z][A-Z0-9_]{0,29}' ).

There seems to be a natural tendency to turn blind to the Don’t-Repeat-Yourself (DRY) principle when there are regular expressions around, compare section Chapter 17: Smells and Heuristics: General: G5: Duplication in Robert C. Martin’s Clean Code.