Using quote delimiter with define off.

Question

I am having issues with the the quote delimiter picking up the colon as a bind variable. For some reason when there is a tick infront of the colon it will break (ex. 2) but in (ex. 3) it is behind the colon it will work fine.
set define off
DECLARE
s1 VARCHAR2(20);
s2 VARCHAR2(20);
s3 VARCHAR2(20);
BEGIN
  s1 := 'Isn''t t:his cool';
  --s2 := q'{Isn't th:is cool}';
  s3 := q'{Isnt th:is co'ol}';
  dbms_output.put_line(s1);
  dbms_output.put_line(s2);
  dbms_output.put_line(s3);
END;
/

Answer 1

@SY,
Can you please explain the difference ?
SQL> select  * from v$version;
BANNER
Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
PL/SQL Release 9.2.0.8.0 - Production
CORE    9.2.0.8.0       Production
TNS for HPUX: Version 9.2.0.8.0 - Production
NLSRTL Version 9.2.0.8.0 - Production
SQL> SET define off
SQL>
SQL> DECLARE
  2     s1   VARCHAR2 (20);
  3     s2   VARCHAR2 (20);
  4     s3   VARCHAR2 (20);
  5  BEGIN
  6     s1 := 'Isn''t t:his cool';
  7     s2 := q'{Isn't th:is cool}';
  8     s3 := q'{Isnt th:is co'ol}';
  9     DBMS_OUTPUT.put_line (s1);
10     DBMS_OUTPUT.put_line (s2);
11     DBMS_OUTPUT.put_line (s3);
12  END;
13  /
   s2 := q'{Isn't th:is cool}';
ERROR at line 7:
ORA-06550: line 7, column 11:
PLS-00103: Encountered the symbol "{Isn" when expecting one of the following:
. ( * @ % & = - + ; < / > at in is mod not rem
<an exponent (**)> <> or != or ~= >= <= <> and or like
between ||
SQL> select * from v$version;
BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
PL/SQL Release 11.2.0.2.0 - Production
CORE    11.2.0.2.0      Production
TNS for Linux: Version 11.2.0.2.0 - Production
NLSRTL Version 11.2.0.2.0 - Production
SQL> SET define off
SQL>
SQL> DECLARE
  2     s1   VARCHAR2 (20);
  3     s2   VARCHAR2 (20);
  4     s3   VARCHAR2 (20);
  5  BEGIN
  6     s1 := 'Isn''t t:his cool';
  7     s2 := q'{Isn't th:is cool}';
  8     s3 := q'{Isnt th:is co'ol}';
  9     DBMS_OUTPUT.put_line (s1);
10     DBMS_OUTPUT.put_line (s2);
11     DBMS_OUTPUT.put_line (s3);
12  END;
13  /
Isn't t:his cool
Isn't th:is cool
Isnt th:is co'ol
PL/SQL procedure successfully completed.Thanks in advance.