Add IS UNKNOWN, IS NOT UNKNOWN boolean tests, fix the existing boolean

tests to return the correct results per SQL9x when given NULL inputs.
Reimplement these tests as well as IS [NOT] NULL to have their own
expression node types, instead of depending on special functions.
From Joe Conway, with a little help from Tom Lane.

1 files changed, 55 insertions, 1 deletions

diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index a83f0b64dbf..2f0dec048b3 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.110 2001/06/05 05:26:04 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.111 2001/06/19 22:39:11 tgl Exp $
  *
  * NOTES
  *	  Most of the read functions for plan nodes are tested. (In fact, they
@@ -860,6 +860,56 @@ _readCaseWhen(void)
 }
 
 /* ----------------
+ *		_readNullTest
+ *
+ *	NullTest is a subclass of Node
+ * ----------------
+ */
+static NullTest *
+_readNullTest(void)
+{
+	NullTest	*local_node;
+	char		*token;
+	int			length;
+
+	local_node = makeNode(NullTest);
+
+	token = pg_strtok(&length); /* eat :arg */
+	local_node->arg = nodeRead(true);	/* now read it */
+
+	token = pg_strtok(&length); /* eat :nulltesttype */
+	token = pg_strtok(&length); /* get nulltesttype */
+	local_node->nulltesttype = (NullTestType) atoi(token);
+
+	return local_node;
+}
+
+/* ----------------
+ *		_readBooleanTest
+ *
+ *	BooleanTest is a subclass of Node
+ * ----------------
+ */
+static BooleanTest *
+_readBooleanTest(void)
+{
+	BooleanTest	*local_node;
+	char		*token;
+	int			length;
+
+	local_node = makeNode(BooleanTest);
+
+	token = pg_strtok(&length); /* eat :arg */
+	local_node->arg = nodeRead(true);	/* now read it */
+
+	token = pg_strtok(&length); /* eat :booltesttype */
+	token = pg_strtok(&length); /* get booltesttype */
+	local_node->booltesttype = (BoolTestType) atoi(token);
+
+	return local_node;
+}
+
+/* ----------------
  *		_readVar
  *
  *	Var is a subclass of Expr
@@ -1966,6 +2016,10 @@ parsePlanString(void)
 		return_value = _readCaseExpr();
 	else if (length == 4 && strncmp(token, "WHEN", length) == 0)
 		return_value = _readCaseWhen();
+	else if (length == 8 && strncmp(token, "NULLTEST", length) == 0)
+		return_value = _readNullTest();
+	else if (length == 11 && strncmp(token, "BOOLEANTEST", length) == 0)
+		return_value = _readBooleanTest();
 	else
 		elog(ERROR, "badly formatted planstring \"%.10s\"...", token);