Over-rigidity in recent to_timestamp() rewrite - Mailing list pgsql-hackers

Whilst poking at bug #4702 I noticed that PG CVS HEAD rejects use of
AD/BC notation, as well as CC (separate century) fields, in combination
with ISO-style day numbers.  I don't see the point of this.  It's
historically inaccurate, no doubt, but so is use of Gregorian counting.
So I suggest the attached fix.  Does this make anyone unhappy?
        regards, tom lane

Index: src/backend/utils/adt/formatting.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v
retrieving revision 1.155
diff -c -r1.155 formatting.c
*** src/backend/utils/adt/formatting.c    12 Mar 2009 00:53:25 -0000    1.155
--- src/backend/utils/adt/formatting.c    14 Mar 2009 17:37:05 -0000
***************
*** 709,721 ****  */ static const KeyWord DCH_keywords[] = { /*    name, len, id, is_digit, date_mode */
!     {"A.D.", 4, DCH_A_D, FALSE, FROM_CHAR_DATE_GREGORIAN},    /* A */     {"A.M.", 4, DCH_A_M, FALSE,
FROM_CHAR_DATE_NONE},
!     {"AD", 2, DCH_AD, FALSE, FROM_CHAR_DATE_GREGORIAN},     {"AM", 2, DCH_AM, FALSE, FROM_CHAR_DATE_NONE},
!     {"B.C.", 4, DCH_B_C, FALSE, FROM_CHAR_DATE_GREGORIAN},    /* B */
!     {"BC", 2, DCH_BC, FALSE, FROM_CHAR_DATE_GREGORIAN},
!     {"CC", 2, DCH_CC, TRUE, FROM_CHAR_DATE_GREGORIAN},        /* C */     {"DAY", 3, DCH_DAY, FALSE,
FROM_CHAR_DATE_NONE},       /* D */     {"DDD", 3, DCH_DDD, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"DD", 2, DCH_DD,
TRUE,FROM_CHAR_DATE_GREGORIAN},
 
--- 709,721 ----  */ static const KeyWord DCH_keywords[] = { /*    name, len, id, is_digit, date_mode */
!     {"A.D.", 4, DCH_A_D, FALSE, FROM_CHAR_DATE_NONE},        /* A */     {"A.M.", 4, DCH_A_M, FALSE,
FROM_CHAR_DATE_NONE},
!     {"AD", 2, DCH_AD, FALSE, FROM_CHAR_DATE_NONE},     {"AM", 2, DCH_AM, FALSE, FROM_CHAR_DATE_NONE},
!     {"B.C.", 4, DCH_B_C, FALSE, FROM_CHAR_DATE_NONE},        /* B */
!     {"BC", 2, DCH_BC, FALSE, FROM_CHAR_DATE_NONE},
!     {"CC", 2, DCH_CC, TRUE, FROM_CHAR_DATE_NONE},            /* C */     {"DAY", 3, DCH_DAY, FALSE,
FROM_CHAR_DATE_NONE},       /* D */     {"DDD", 3, DCH_DDD, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"DD", 2, DCH_DD,
TRUE,FROM_CHAR_DATE_GREGORIAN},
 
***************
*** 757,769 ****     {"YYY", 3, DCH_YYY, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"YY", 2, DCH_YY, TRUE,
FROM_CHAR_DATE_GREGORIAN},    {"Y", 1, DCH_Y, TRUE, FROM_CHAR_DATE_GREGORIAN},
 
!     {"a.d.", 4, DCH_a_d, FALSE, FROM_CHAR_DATE_GREGORIAN},    /* a */     {"a.m.", 4, DCH_a_m, FALSE,
FROM_CHAR_DATE_NONE},
!     {"ad", 2, DCH_ad, FALSE, FROM_CHAR_DATE_GREGORIAN},     {"am", 2, DCH_am, FALSE, FROM_CHAR_DATE_NONE},
!     {"b.c.", 4, DCH_b_c, FALSE, FROM_CHAR_DATE_GREGORIAN},    /* b */
!     {"bc", 2, DCH_bc, FALSE, FROM_CHAR_DATE_GREGORIAN},
!     {"cc", 2, DCH_CC, TRUE, FROM_CHAR_DATE_GREGORIAN},        /* c */     {"day", 3, DCH_day, FALSE,
FROM_CHAR_DATE_NONE},       /* d */     {"ddd", 3, DCH_DDD, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"dd", 2, DCH_DD,
TRUE,FROM_CHAR_DATE_GREGORIAN},
 
--- 757,769 ----     {"YYY", 3, DCH_YYY, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"YY", 2, DCH_YY, TRUE,
FROM_CHAR_DATE_GREGORIAN},    {"Y", 1, DCH_Y, TRUE, FROM_CHAR_DATE_GREGORIAN},
 
!     {"a.d.", 4, DCH_a_d, FALSE, FROM_CHAR_DATE_NONE},        /* a */     {"a.m.", 4, DCH_a_m, FALSE,
FROM_CHAR_DATE_NONE},
!     {"ad", 2, DCH_ad, FALSE, FROM_CHAR_DATE_NONE},     {"am", 2, DCH_am, FALSE, FROM_CHAR_DATE_NONE},
!     {"b.c.", 4, DCH_b_c, FALSE, FROM_CHAR_DATE_NONE},        /* b */
!     {"bc", 2, DCH_bc, FALSE, FROM_CHAR_DATE_NONE},
!     {"cc", 2, DCH_CC, TRUE, FROM_CHAR_DATE_NONE},            /* c */     {"day", 3, DCH_day, FALSE,
FROM_CHAR_DATE_NONE},       /* d */     {"ddd", 3, DCH_DDD, TRUE, FROM_CHAR_DATE_GREGORIAN},     {"dd", 2, DCH_DD,
TRUE,FROM_CHAR_DATE_GREGORIAN},