Remove Value node struct

The Value node struct is a weird construct.  It is its own node type,
but most of the time, it actually has a node type of Integer, Float,
String, or BitString.  As a consequence, the struct name and the node
type don't match most of the time, and so it has to be treated
specially a lot.  There doesn't seem to be any value in the special
construct.  There is very little code that wants to accept all Value
variants but nothing else (and even if it did, this doesn't provide
any convenient way to check it), and most code wants either just one
particular node type (usually String), or it accepts a broader set of
node types besides just Value.

This change removes the Value struct and node type and replaces them
by separate Integer, Float, String, and BitString node types that are
proper node types and structs of their own and behave mostly like
normal node types.

Also, this removes the T_Null node tag, which was previously also a
possible variant of Value but wasn't actually used outside of the
Value contained in A_Const.  Replace that by an isnull field in
A_Const.

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5ba6bc5b-3f95-04f2-2419-f8ddb4c046fb@enterprisedb.com

1 files changed, 6 insertions, 6 deletions

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 4bdab30a734..76d4fea21c4 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -101,9 +101,9 @@ enum FdwModifyPrivateIndex
 	FdwModifyPrivateUpdateSql,
 	/* Integer list of target attribute numbers for INSERT/UPDATE */
 	FdwModifyPrivateTargetAttnums,
-	/* Length till the end of VALUES clause (as an integer Value node) */
+	/* Length till the end of VALUES clause (as an Integer node) */
 	FdwModifyPrivateLen,
-	/* has-returning flag (as an integer Value node) */
+	/* has-returning flag (as an Integer node) */
 	FdwModifyPrivateHasReturning,
 	/* Integer list of attribute numbers retrieved by RETURNING */
 	FdwModifyPrivateRetrievedAttrs
@@ -122,11 +122,11 @@ enum FdwDirectModifyPrivateIndex
 {
 	/* SQL statement to execute remotely (as a String node) */
 	FdwDirectModifyPrivateUpdateSql,
-	/* has-returning flag (as an integer Value node) */
+	/* has-returning flag (as an Integer node) */
 	FdwDirectModifyPrivateHasReturning,
 	/* Integer list of attribute numbers retrieved by RETURNING */
 	FdwDirectModifyPrivateRetrievedAttrs,
-	/* set-processed flag (as an integer Value node) */
+	/* set-processed flag (as an Integer node) */
 	FdwDirectModifyPrivateSetProcessed
 };
 
@@ -280,9 +280,9 @@ typedef struct PgFdwAnalyzeState
  */
 enum FdwPathPrivateIndex
 {
-	/* has-final-sort flag (as an integer Value node) */
+	/* has-final-sort flag (as an Integer node) */
 	FdwPathPrivateHasFinalSort,
-	/* has-limit flag (as an integer Value node) */
+	/* has-limit flag (as an Integer node) */
 	FdwPathPrivateHasLimit
 };