Re: [HACKERS] Please rename split(text,text,int) to splitpart - Mailing list pgsql-patches

Joe Conway wrote:
 > Hannu Krosing wrote:
 >
 >> It seems that my last mail on this did not get through to the list
 >> ;(
 >>
 >> Please consider renaming the new builtin function
 >> split(text,text,int)
 >>
 >> to something else, perhaps
 >>
 >> split_part(text,text,int)
 >>
 >> (like date_part)
 >>
 >> The reason for this request is that 3 most popular scripting
 >> languages (perl, python, php) all have also a function with similar
 >> signature, but returning an array instead of single element and the
 >> (optional) third argument is limit (maximum number of splits to
 >> perform)
 >>
 >> I think that it would be good to have similar function in (some
 >> future release of) postgres, but if we now let in a function with
 >> same name and arguments but returning a single string instead an
 >> array of them, then we will need to invent a new and not so easy to
 >> recognise name for the "real" split function.
 >>
 >
 > This is a good point, and I'm not opposed to changing the name, but
 > it is too bad your original email didn't get through before beta1 was
 >  rolled. The change would now require an initdb, which I know we were
 >  trying to avoid once beta started (although we could change it
 > without *requiring* an initdb I suppose).
 >
 > I guess if we do end up needing an initdb for other reasons, we
 > should make this change too. Any other opinions? Is split_part an
 > acceptable name?
 >
 > Also, if we add a todo to produce a "real" split function that
 > returns an array, similar to those languages, I'll take it for 7.4.

No one commented on the choice of name, so the attached patch changes
the name of split(text,text,int) to split_part(text,text,int) per
Hannu's recommendation above. This can be applied without an initdb if
current beta testers are advised to run:

   update pg_proc set proname = 'split_part' where proname = 'split';

in the case they want to use this function. Regression and doc fix is
also included in the patch.

Please apply.

Thanks,

Joe

Index: src/include/catalog/pg_proc.h
===================================================================
RCS file: /opt/src/cvs/pgsql-server/src/include/catalog/pg_proc.h,v
retrieving revision 1.270
diff -c -r1.270 pg_proc.h
*** src/include/catalog/pg_proc.h    4 Sep 2002 20:31:38 -0000    1.270
--- src/include/catalog/pg_proc.h    7 Sep 2002 18:54:57 -0000
***************
*** 2130,2136 ****
  DESCR("return portion of string");
  DATA(insert OID =  2087 ( replace       PGNSP PGUID 12 f f t f i 3 25 "25 25 25"  replace_text - _null_ ));
  DESCR("replace all occurrences of old_substr with new_substr in string");
! DATA(insert OID =  2088 ( split           PGNSP PGUID 12 f f t f i 3 25 "25 25 23"  split_text - _null_ ));
  DESCR("split string by field_sep and return field_num");
  DATA(insert OID =  2089 ( to_hex       PGNSP PGUID 12 f f t f i 1 25 "23"  to_hex32 - _null_ ));
  DESCR("convert int32 number to hex");
--- 2130,2136 ----
  DESCR("return portion of string");
  DATA(insert OID =  2087 ( replace       PGNSP PGUID 12 f f t f i 3 25 "25 25 25"  replace_text - _null_ ));
  DESCR("replace all occurrences of old_substr with new_substr in string");
! DATA(insert OID =  2088 ( split_part   PGNSP PGUID 12 f f t f i 3 25 "25 25 23"  split_text - _null_ ));
  DESCR("split string by field_sep and return field_num");
  DATA(insert OID =  2089 ( to_hex       PGNSP PGUID 12 f f t f i 1 25 "23"  to_hex32 - _null_ ));
  DESCR("convert int32 number to hex");
Index: src/test/regress/expected/strings.out
===================================================================
RCS file: /opt/src/cvs/pgsql-server/src/test/regress/expected/strings.out,v
retrieving revision 1.16
diff -c -r1.16 strings.out
*** src/test/regress/expected/strings.out    28 Aug 2002 20:18:29 -0000    1.16
--- src/test/regress/expected/strings.out    7 Sep 2002 19:09:44 -0000
***************
*** 719,747 ****
  (1 row)

  --
! -- test split
  --
! select split('joeuser@mydatabase','@',0) AS "an error";
  ERROR:  field position must be > 0
! select split('joeuser@mydatabase','@',1) AS "joeuser";
   joeuser
  ---------
   joeuser
  (1 row)

! select split('joeuser@mydatabase','@',2) AS "mydatabase";
   mydatabase
  ------------
   mydatabase
  (1 row)

! select split('joeuser@mydatabase','@',3) AS "empty string";
   empty string
  --------------

  (1 row)

! select split('@joeuser@mydatabase@','@',2) AS "joeuser";
   joeuser
  ---------
   joeuser
--- 719,747 ----
  (1 row)

  --
! -- test split_part
  --
! select split_part('joeuser@mydatabase','@',0) AS "an error";
  ERROR:  field position must be > 0
! select split_part('joeuser@mydatabase','@',1) AS "joeuser";
   joeuser
  ---------
   joeuser
  (1 row)

! select split_part('joeuser@mydatabase','@',2) AS "mydatabase";
   mydatabase
  ------------
   mydatabase
  (1 row)

! select split_part('joeuser@mydatabase','@',3) AS "empty string";
   empty string
  --------------

  (1 row)

! select split_part('@joeuser@mydatabase@','@',2) AS "joeuser";
   joeuser
  ---------
   joeuser
Index: src/test/regress/sql/strings.sql
===================================================================
RCS file: /opt/src/cvs/pgsql-server/src/test/regress/sql/strings.sql,v
retrieving revision 1.10
diff -c -r1.10 strings.sql
*** src/test/regress/sql/strings.sql    28 Aug 2002 20:18:29 -0000    1.10
--- src/test/regress/sql/strings.sql    7 Sep 2002 19:09:00 -0000
***************
*** 288,304 ****
  SELECT replace('yabadoo', 'bad', '') AS "yaoo";

  --
! -- test split
  --
! select split('joeuser@mydatabase','@',0) AS "an error";

! select split('joeuser@mydatabase','@',1) AS "joeuser";

! select split('joeuser@mydatabase','@',2) AS "mydatabase";

! select split('joeuser@mydatabase','@',3) AS "empty string";

! select split('@joeuser@mydatabase@','@',2) AS "joeuser";

  --
  -- test to_hex
--- 288,304 ----
  SELECT replace('yabadoo', 'bad', '') AS "yaoo";

  --
! -- test split_part
  --
! select split_part('joeuser@mydatabase','@',0) AS "an error";

! select split_part('joeuser@mydatabase','@',1) AS "joeuser";

! select split_part('joeuser@mydatabase','@',2) AS "mydatabase";

! select split_part('joeuser@mydatabase','@',3) AS "empty string";

! select split_part('@joeuser@mydatabase@','@',2) AS "joeuser";

  --
  -- test to_hex
Index: doc/src/sgml/func.sgml
===================================================================
RCS file: /opt/src/cvs/pgsql-server/doc/src/sgml/func.sgml,v
retrieving revision 1.120
diff -c -r1.120 func.sgml
*** doc/src/sgml/func.sgml    2 Sep 2002 05:53:23 -0000    1.120
--- doc/src/sgml/func.sgml    7 Sep 2002 19:12:34 -0000
***************
*** 1899,1912 ****
        </row>

        <row>
!        <entry><function>split</function>(<parameter>string</parameter> <type>text</type>,
         <parameter>delimiter</parameter> <type>text</type>,
         <parameter>column</parameter> <type>integer</type>)</entry>
         <entry><type>text</type></entry>
         <entry>Split <parameter>string</parameter> on <parameter>delimiter</parameter>
          returning the resulting (one based) <parameter>column</parameter> number.
         </entry>
!        <entry><literal>split('abc~@~def~@~ghi','~@~',2)</literal></entry>
         <entry><literal>def</literal></entry>
        </row>

--- 1899,1912 ----
        </row>

        <row>
!        <entry><function>split_part</function>(<parameter>string</parameter> <type>text</type>,
         <parameter>delimiter</parameter> <type>text</type>,
         <parameter>column</parameter> <type>integer</type>)</entry>
         <entry><type>text</type></entry>
         <entry>Split <parameter>string</parameter> on <parameter>delimiter</parameter>
          returning the resulting (one based) <parameter>column</parameter> number.
         </entry>
!        <entry><literal>split_part('abc~@~def~@~ghi','~@~',2)</literal></entry>
         <entry><literal>def</literal></entry>
        </row>