PL/SQL short-cut evaluation

shortcut_plsql.sql

-- Coalesce has short-cut evaluation so it does not evaluate second parameter if the
-- first one is ok
DECLARE
  num_Result                     NUMBER;
  num_Something                  NUMBER := 1;
  --
  FUNCTION RAISES
  RETURN NUMBER
  IS
  BEGIN
    RAISE_APPLICATION_ERROR(-20100, 'Here be dragons');

    RETURN 0;
  END RAISES;
BEGIN
  num_Result := COALESCE(num_Something, RAISES);
  
  RAISE_APPLICATION_ERROR(-20101, num_Result);
END;
/
-- If it is not, wll, then everything goes as expected
DECLARE
  num_Result                     NUMBER;
  num_Something                  NUMBER;
  --
  FUNCTION RAISES
  RETURN NUMBER
  IS
  BEGIN
    RAISE_APPLICATION_ERROR(-20100, 'Here be dragons');

    RETURN 0;
  END RAISES;
BEGIN
  num_Result := COALESCE(num_Something, RAISES);
  
  RAISE_APPLICATION_ERROR(-20101, num_Result);
END;
/
-- NVL has no short-cut evaluation
DECLARE
  num_Result                     NUMBER;
  num_Something                  NUMBER;
  --
  FUNCTION RAISES
  RETURN NUMBER
  IS
  BEGIN
    RAISE_APPLICATION_ERROR(-20100, 'Here be dragons');

    RETURN 0;
  END RAISES;
BEGIN
  num_Result := NVL(num_Something, RAISES);
  
  RAISE_APPLICATION_ERROR(-20101, num_Result);
END;
/