Extend ctx_thes.syn to return formatted synonyms

Question

I am using Oracle 11.2.0.3. We have oracle context text index and have implemented thesaurus on selected few words.
Let say:
select ctx_thes.syn('nathan') from dual;
gives me
{nathan}| {nate}
However, I want   it to return nathan%| nate%  without  curly bracket and adding wildcard character.
Since , oracle text index is extensible indexing framework, is it possible to change ctx_thes.syn  to meet my requirement or should I write my custom code. If  I need to write a custom code, which table should I be looking into.
Thanks.

Answer 1

Regarding the above  test_proc, I am getting lots of NULL and some values are not preset. Is that expected?...
I think you may have copied a version of the procedure before I corrected it.  I added a sub-query that returns one row, instead of using dual.  That eliminates joining to every row in the table.  The other thing that causes null values is if there are double spaces in your data.  Please see the following example that shows what the corrected procedure returns.  Note that if there are triple spaces and such, then you would have to allow for that.  There are many was to tokenize strings and you can use whichever you like.  All of the special characters in the output below are ignored during indexing, so you end up with just the tokenized individual words.
SCOTT@orcl12c> begin
  2    ctx_thes.create_thesaurus ('test_thes');
  3    ctx_thes.create_relation ('test_thes', 'nathan', 'SYN', 'nate');
  4  end;
  5  /
PL/SQL procedure successfully completed.
SCOTT@orcl12c> create table org
  2        AS (SELECT 1 org_pk, 'ALL american  ,INC' org_nm FROM DUAL
  3            UNION ALL
  4            SELECT 2 org_pk, 'A.G  COMPANY' org_nm FROM DUAL
  5            UNION ALL
  6            SELECT 3 org_pk, 'GROWTH FUND SPONSORS and SONS, INC.' org_nm FROM DUAL)
  7  /
Table created.
SCOTT@orcl12c> insert all
  2  into org values (4, 'nate')
  3  into org values (5, 'nathaniel')
  4  into org values (6, 'nathin')
  5  into org values (7, 'nobody')
  6  into org values (8, 'Nathan Myhrvold')
  7  into org values (9, 'Nat King Cole')
  8  into org values (10, 'adviser')
  9  into org values (11, 'advisor')
10  into org values (12, 'advisers')
11  into org values (13, 'advisors')
12  into org values (14, 'advisory')
13  select * from dual
14  /
11 rows created.
SCOTT@orcl12c> create or replace procedure test_proc
  2    (p_rid  in         rowid,
  3      p_clob in out nocopy clob)
  4  as
  5  begin
  6    for r1 in
  7       (select ctx_thes.syn
  8             (trim (regexp_substr (org_nm, '[^ ]+', 1, rownum)),
  9              'test_thes') token
10        from     (select org_nm from org where rowid = p_rid)
11        connect by level <= regexp_count (replace (org_nm, '    ', ' '), ' ') + 1)
12    loop
13       dbms_lob.writeappend (p_clob, length (r1.token), r1.token);
14    end loop;
15  end test_proc;
16  /
Procedure created.
SCOTT@orcl12c> show errors
No errors.
SCOTT@orcl12c> declare
  2    v_clob  clob;
  3  begin
  4    for r in (select rowid from org) loop
  5       dbms_lob.createtemporary (v_clob, true);
  6       test_proc (r.rowid, v_clob);
  7       dbms_output.put_line (v_clob);
  8       dbms_lob.freetemporary (v_clob);
  9    end loop;
10  end;
11  /
{ALL}{AMERICAN}{,INC}
{A.G}{COMPANY}
{GROWTH}{FUND}{SPONSORS}{AND}{SONS,}{INC.}
{NATE}|{NATHAN}
{NATHANIEL}
{NATHIN}
{NOBODY}
{NATHAN}|{NATE}{MYHRVOLD}
{NAT}{KING}{COLE}
{ADVISER}
{ADVISOR}
{ADVISERS}
{ADVISORS}
{ADVISORY}
PL/SQL procedure successfully completed.
SCOTT@orcl12c>