All regression tests pass except for rules.sql (unrelated).

Implement "date/time grand unification".
 Transform datetime and timespan into timestamp and interval.
 Deprecate datetime and timespan, though translate to new types in gram.y.
 Transform all datetime and timespan catalog entries into new types.
 Make "INTERVAL" reserved word allowed as a column identifier in gram.y.
 Remove dt.h, dt.c files, and retarget datetime.h, datetime.c as utility
  routines for all date/time types.
 date.{h,c} now deals with date, time types.
 timestamp.{h,c} now deals with timestamp, interval types.
 nabstime.{h,c} now deals with abstime, reltime, tinterval types.
Make NUMERIC a known native type for purposes of type coersion. Not tested.

Author: Thomas G. Lockhart

src/test/regress/expected/horology.out

@@ -1,24 +1,24 @@
 --
--- TIMESPAN
+-- INTERVAL
 --
-CREATE TABLE TIMESPAN_TBL (f1 timespan);
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 1 minute');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 5 hour');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 10 day');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 34 year');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 3 months');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 14 seconds ago');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('1 day 2 hours 3 minutes 4 seconds');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('6 years');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('5 months');
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('5 months 12 hours');
--- badly formatted timespan
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('badly formatted timespan');
-ERROR:  Bad timespan external representation 'badly formatted timespan'
-INSERT INTO TIMESPAN_TBL (f1) VALUES ('@ 30 eons ago');
-ERROR:  Bad timespan external representation '@ 30 eons ago'
--- test timespan operators
-SELECT '' AS ten, TIMESPAN_TBL.*;
+CREATE TABLE INTERVAL_TBL (f1 interval);
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 1 minute');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 5 hour');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 10 day');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 34 year');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 3 months');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 14 seconds ago');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('1 day 2 hours 3 minutes 4 seconds');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('6 years');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('5 months');
+INSERT INTO INTERVAL_TBL (f1) VALUES ('5 months 12 hours');
+-- badly formatted interval
+INSERT INTO INTERVAL_TBL (f1) VALUES ('badly formatted interval');
+ERROR:  Bad interval external representation 'badly formatted interval'
+INSERT INTO INTERVAL_TBL (f1) VALUES ('@ 30 eons ago');
+ERROR:  Bad interval external representation '@ 30 eons ago'
+-- test interval operators
+SELECT '' AS ten, INTERVAL_TBL.*;
  ten |              f1               
 -----+-------------------------------
      | @ 1 min
@@ -33,8 +33,8 @@ SELECT '' AS ten, TIMESPAN_TBL.*;
      | @ 5 mons 12 hours
 (10 rows)
 
-SELECT '' AS nine, TIMESPAN_TBL.*
-   WHERE TIMESPAN_TBL.f1 <> timespan '@ 10 days';
+SELECT '' AS nine, INTERVAL_TBL.*
+   WHERE INTERVAL_TBL.f1 <> interval '@ 10 days';
  nine |              f1               
 ------+-------------------------------
       | @ 1 min
@@ -48,33 +48,33 @@ SELECT '' AS nine, TIMESPAN_TBL.*
       | @ 5 mons 12 hours
 (9 rows)
 
-SELECT '' AS three, TIMESPAN_TBL.*
-   WHERE TIMESPAN_TBL.f1 <= timespan '@ 5 hours';
+SELECT '' AS three, INTERVAL_TBL.*
+   WHERE INTERVAL_TBL.f1 <= interval '@ 5 hours';
  three |      f1       
 -------+---------------
        | @ 1 min
        | @ 5 hours
        | @ 14 secs ago
 (3 rows)
 
-SELECT '' AS three, TIMESPAN_TBL.*
-   WHERE TIMESPAN_TBL.f1 < timespan '@ 1 day';
+SELECT '' AS three, INTERVAL_TBL.*
+   WHERE INTERVAL_TBL.f1 < interval '@ 1 day';
  three |      f1       
 -------+---------------
        | @ 1 min
        | @ 5 hours
        | @ 14 secs ago
 (3 rows)
 
-SELECT '' AS one, TIMESPAN_TBL.*
-   WHERE TIMESPAN_TBL.f1 = timespan '@ 34 years';
+SELECT '' AS one, INTERVAL_TBL.*
+   WHERE INTERVAL_TBL.f1 = interval '@ 34 years';
  one |     f1     
 -----+------------
      | @ 34 years
 (1 row)
 
-SELECT '' AS five, TIMESPAN_TBL.* 
-   WHERE TIMESPAN_TBL.f1 >= timespan '@ 1 month';
+SELECT '' AS five, INTERVAL_TBL.* 
+   WHERE INTERVAL_TBL.f1 >= interval '@ 1 month';
  five |        f1         
 ------+-------------------
       | @ 34 years
@@ -84,8 +84,8 @@ SELECT '' AS five, TIMESPAN_TBL.*
       | @ 5 mons 12 hours
 (5 rows)
 
-SELECT '' AS nine, TIMESPAN_TBL.*
-   WHERE TIMESPAN_TBL.f1 > timespan '@ 3 seconds ago';
+SELECT '' AS nine, INTERVAL_TBL.*
+   WHERE INTERVAL_TBL.f1 > interval '@ 3 seconds ago';
  nine |              f1               
 ------+-------------------------------
       | @ 1 min
@@ -100,7 +100,7 @@ SELECT '' AS nine, TIMESPAN_TBL.*
 (9 rows)
 
 SELECT '' AS fortyfive, r1.*, r2.*
-   FROM TIMESPAN_TBL r1, TIMESPAN_TBL r2
+   FROM INTERVAL_TBL r1, INTERVAL_TBL r2
    WHERE r1.f1 > r2.f1
    ORDER BY r1.f1, r2.f1;
  fortyfive |              f1               |              f1