Change NOTICE/NOTICE/NOTICE/WARN elog messages to a single message
 with a few newline/tab breaks embedded in the string. Much cleaner I hope.

 and from SELECT ... INTO ... support code.
Allow NOT, IS NULL, IS NOT NULL in constraints.
Define unionall boolean flag in SubSelect structure.
Implement row descriptors: (a, b, c) = (x, y, z).
Change IS TRUE, IS FALSE, etc. to expressions using "=" rather than
 function calls to istrue() or isfalse() to allow optimization.
Force type for TRUE and FALSE to bool.

 Formerly allowed only single arguments.
Declare column constraints using the usual list mechanism rather
 than explicit itemized lists.
Remove NOTNULL from default clause syntax (retain "NOT NULL").
 NOTNULL is not SQL92; eventually remove it from expressions too?
Move ISNULL, NOTNULL to Postgres-specific token declarations.
Fix up tabs and indenting on new CREATE USER commands.

Implement PRIMARY KEY and UNIQUE clauses using indices.

An extension to the code to allow for a pg_password authentication database
that is *seperate* from the system password file

Change elog WARN to NOTICE for unimplemented constraints.

 to NOTICE messages so that execution proceeds rather than halting.
 These clauses are ignored as stated in the messages.
Allow NOT NULL UNIQUE syntax (both were allowed individually before).
Allow Postgres-style casting ("::") of non-constants.

Support SQL92 syntax for type coersion of strings (type 'typeval').
 Example: "DATETIME 'now'". This works only for string constants and can
 not replace the CAST and ::type syntax which behave identically in this
 context.

available.
Remove lots of #ifdef'd debugging print statements.

Implement SET keyword = DEFAULT and SET TIME ZONE DEFAULT.
Re-enable JOIN= option in CREATE OPERATOR statement (damaged for v6.2).
Allow more SQL and/or Postgres reserved words as column identifiers
 or, if there are shift/reduce problems, at least as column labels.

Add support for SQL3 IS TRUE and IS FALSE.
Augment support for SQL92 SET TIME ZONE...

 CURRENT_USER.
Add syntax for primary and foreign keys.
Change optional syntax in CREATE INDEX to avoid parsing conflict with
 TIMESTAMP WITH TIME ZONE data type (use USING <class> rather than WITH...).
Decouple various categories of data type syntax to allow the most possible
 non-ambiguous extensions to SQL92 for column names and labels. This should
 make the parser a bit more understandable, or at least easier to find
 where and how the data types are handled.
Support syntax for IN and EXISTS clauses with subselects.
Support SQL92 syntax for IS TRUE/IS FALSE/IS NOT TRUE/IS NOT FALSE.

Add SQL/92 types decimal and numeric (temporary for syntax support).
 These types need more support in the backend to be really implemented,
 and the parser will need to be changed at that time.
Adjust limits on precision parameters for FLOAT(p) to match IEEE-compliant
 arithmetic. Perhaps these limits should be processor-specific or obtained
 from system include files instead.

Allow use IDENT as arguments of trigger functions