pg_cast table, and standards-compliant CREATE/DROP CAST commands, plus

extension to create binary compatible casts.  Includes dependency tracking
as well.

pg_proc.proimplicit is now defunct, but will be removed in a separate
commit.

pg_dump provides a migration path from the previous scheme to declare
casts.  Dumping binary compatible casts is currently impossible, though.

src/backend/catalog/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for backend/catalog
 #
-# $Header: /cvsroot/pgsql/src/backend/catalog/Makefile,v 1.41 2002/07/12 18:43:13 tgl Exp $
+# $Header: /cvsroot/pgsql/src/backend/catalog/Makefile,v 1.42 2002/07/18 23:11:27 petere Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -30,7 +30,7 @@ POSTGRES_BKI_SRCS := $(addprefix $(top_srcdir)/src/include/catalog/,\
 	pg_attrdef.h pg_constraint.h pg_inherits.h pg_index.h \
 	pg_operator.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
 	pg_language.h pg_largeobject.h pg_aggregate.h pg_statistic.h \
-	pg_rewrite.h pg_trigger.h pg_listener.h pg_description.h \
+	pg_rewrite.h pg_trigger.h pg_listener.h pg_description.h pg_cast.h \
 	pg_namespace.h pg_conversion.h pg_database.h pg_shadow.h pg_group.h \
 	pg_depend.h indexing.h \
     )

src/backend/catalog/dependency.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/dependency.c,v 1.4 2002/07/18 16:47:22 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/dependency.c,v 1.5 2002/07/18 23:11:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -47,6 +47,7 @@
 /* This enum covers all system catalogs whose OIDs can appear in classid. */
 typedef enum ObjectClasses
 {
+	OCLASS_CAST,				/* pg_cast */
 	OCLASS_CLASS,				/* pg_class */
 	OCLASS_PROC,				/* pg_proc */
 	OCLASS_TYPE,				/* pg_type */
@@ -604,6 +605,10 @@ doDeletion(const ObjectAddress *object)
 			RemoveSchemaById(object->objectId);
 			break;
 
+		case OCLASS_CAST:
+			DropCastById(object->objectId);
+			break;
+
 		default:
 			elog(ERROR, "doDeletion: Unsupported object class %u",
 				 object->classId);
@@ -979,6 +984,7 @@ term_object_addresses(ObjectAddresses *addrs)
 static void
 init_object_classes(void)
 {
+	object_classes[OCLASS_CAST] = get_system_catalog_relid(CastRelationName);
 	object_classes[OCLASS_CLASS] = RelOid_pg_class;
 	object_classes[OCLASS_PROC] = RelOid_pg_proc;
 	object_classes[OCLASS_TYPE] = RelOid_pg_type;
@@ -1023,6 +1029,11 @@ getObjectClass(const ObjectAddress *object)
 	if (!object_classes_initialized)
 		init_object_classes();
 
+	if (object->classId == object_classes[OCLASS_CAST])
+	{
+		Assert(object->objectSubId == 0);
+		return OCLASS_CAST;
+	}
 	if (object->classId == object_classes[OCLASS_CONSTRAINT])
 	{
 		Assert(object->objectSubId == 0);
@@ -1078,6 +1089,10 @@ getObjectDescription(const ObjectAddress *object)
 
 	switch (getObjectClass(object))
 	{
+		case OCLASS_CAST:
+			appendStringInfo(&buffer, "cast");
+			break;
+
 		case OCLASS_CLASS:
 			getRelationDescription(&buffer, object->objectId);
 			if (object->objectSubId != 0)

src/backend/catalog/indexing.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.97 2002/07/15 16:33:31 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.98 2002/07/18 23:11:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -43,6 +43,8 @@ char	   *Name_pg_attr_indices[Num_pg_attr_indices] =
 {AttributeRelidNameIndex, AttributeRelidNumIndex};
 char	   *Name_pg_attrdef_indices[Num_pg_attrdef_indices] =
 {AttrDefaultIndex, AttrDefaultOidIndex};
+char	   *Name_pg_cast_indices[Num_pg_cast_indices] =
+{CastSourceTargetIndex};
 char	   *Name_pg_class_indices[Num_pg_class_indices] =
 {ClassNameNspIndex, ClassOidIndex};
 char	   *Name_pg_constraint_indices[Num_pg_constraint_indices] =

src/backend/catalog/pg_aggregate.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.50 2002/07/16 22:12:18 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.51 2002/07/18 23:11:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -144,7 +144,6 @@ AggregateCreate(const char *aggName,
 							  "-",			/* probin */
 							  true,			/* isAgg */
 							  false,		/* security invoker (currently not definable for agg) */
-							  false,		/* isImplicit */
 							  false,		/* isStrict (not needed for agg) */
 							  PROVOLATILE_IMMUTABLE,	/* volatility (not needed for agg) */
 							  BYTE_PCT,		/* default cost values */

src/backend/catalog/pg_proc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.78 2002/07/18 16:47:23 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_proc.c,v 1.79 2002/07/18 23:11:27 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -55,7 +55,6 @@ ProcedureCreate(const char *procedureName,
 				const char *probin,
 				bool isAgg,
 				bool security_definer,
-				bool isImplicit,
 				bool isStrict,
 				char volatility,
 				int32 byte_pct,
@@ -163,7 +162,7 @@ ProcedureCreate(const char *procedureName,
 	values[i++] = ObjectIdGetDatum(languageObjectId); /* prolang */
 	values[i++] = BoolGetDatum(isAgg);			/* proisagg */
 	values[i++] = BoolGetDatum(security_definer); /* prosecdef */
-	values[i++] = BoolGetDatum(isImplicit);		/* proimplicit */
+	values[i++] = BoolGetDatum(false);			/* proimplicit */
 	values[i++] = BoolGetDatum(isStrict);		/* proisstrict */
 	values[i++] = BoolGetDatum(returnsSet);		/* proretset */
 	values[i++] = CharGetDatum(volatility);		/* provolatile */

src/backend/commands/functioncmds.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/functioncmds.c,v 1.8 2002/07/12 18:43:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/functioncmds.c,v 1.9 2002/07/18 23:11:27 petere Exp $
  *
  * DESCRIPTION
  *	  These routines take the parse tree and pick out the
@@ -34,7 +34,9 @@
 #include "access/heapam.h"
 #include "catalog/catname.h"
 #include "catalog/dependency.h"
+#include "catalog/indexing.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_cast.h"
 #include "catalog/pg_language.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
@@ -44,6 +46,7 @@
 #include "parser/parse_func.h"
 #include "parser/parse_type.h"
 #include "utils/acl.h"
+#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
 
@@ -171,8 +174,7 @@ compute_attributes_sql_style(const List *options,
 							 char **language,
 							 char *volatility_p,
 							 bool *strict_p,
-							 bool *security_definer,
-							 bool *implicit_cast)
+							 bool *security_definer)
 {
 	const List *option;
 	DefElem *as_item = NULL;
@@ -180,7 +182,6 @@ compute_attributes_sql_style(const List *options,
 	DefElem *volatility_item = NULL;
 	DefElem *strict_item = NULL;
 	DefElem *security_item = NULL;
-	DefElem *implicit_item = NULL;
 
 	foreach(option, options)
 	{
@@ -216,12 +217,6 @@ compute_attributes_sql_style(const List *options,
 				elog(ERROR, "conflicting or redundant options");
 			security_item = defel;
 		}
-		else if (strcmp(defel->defname, "implicit")==0)
-		{
-			if (implicit_item)
-				elog(ERROR, "conflicting or redundant options");
-			implicit_item = defel;
-		}
 		else
 			elog(ERROR, "invalid CREATE FUNCTION option");
 	}
@@ -252,8 +247,6 @@ compute_attributes_sql_style(const List *options,
 		*strict_p = intVal(strict_item->arg);
 	if (security_item)
 		*security_definer = intVal(security_item->arg);
-	if (implicit_item)
-		*implicit_cast = intVal(implicit_item->arg);
 }
 
 
@@ -264,10 +257,7 @@ compute_attributes_sql_style(const List *options,
  *	These parameters supply optional information about a function.
  *	All have defaults if not specified.
  *
- *	Note: currently, only three of these parameters actually do anything:
- *
- *	 * isImplicit means the function may be used as an implicit type
- *	   coercion.
+ *	Note: currently, only two of these parameters actually do anything:
  *
  *	 * isStrict means the function should not be called when any NULL
  *	   inputs are present; instead a NULL result value should be assumed.
@@ -284,7 +274,7 @@ static void
 compute_attributes_with_style(List *parameters,
 							  int32 *byte_pct_p, int32 *perbyte_cpu_p,
 							  int32 *percall_cpu_p, int32 *outin_ratio_p,
-							  bool *isImplicit_p, bool *isStrict_p,
+							  bool *isStrict_p,
 							  char *volatility_p)
 {
 	List	   *pl;
@@ -293,9 +283,7 @@ compute_attributes_with_style(List *parameters,
 	{
 		DefElem    *param = (DefElem *) lfirst(pl);
 
-		if (strcasecmp(param->defname, "implicitcoercion") == 0)
-			*isImplicit_p = true;
-		else if (strcasecmp(param->defname, "isstrict") == 0)
+		if (strcasecmp(param->defname, "isstrict") == 0)
 			*isStrict_p = true;
 		else if (strcasecmp(param->defname, "isimmutable") == 0)
 			*volatility_p = PROVOLATILE_IMMUTABLE;
@@ -398,8 +386,7 @@ CreateFunction(CreateFunctionStmt *stmt)
 				perbyte_cpu,
 				percall_cpu,
 				outin_ratio;
-	bool		isImplicit,
-				isStrict,
+	bool		isStrict,
 				security;
 	char		volatility;
 	HeapTuple	languageTuple;
@@ -420,14 +407,13 @@ CreateFunction(CreateFunctionStmt *stmt)
 	perbyte_cpu = PERBYTE_CPU;
 	percall_cpu = PERCALL_CPU;
 	outin_ratio = OUTIN_RATIO;
-	isImplicit = false;
 	isStrict = false;
 	security = false;
 	volatility = PROVOLATILE_VOLATILE;
 
 	/* override attributes from explicit list */
 	compute_attributes_sql_style(stmt->options,
-								 &as_clause, &language, &volatility, &isStrict, &security, &isImplicit);
+								 &as_clause, &language, &volatility, &isStrict, &security);
 
 	/* Convert language name to canonical case */
 	case_translate_language_name(language, languageName);
@@ -474,8 +460,7 @@ CreateFunction(CreateFunctionStmt *stmt)
 
 	compute_attributes_with_style(stmt->withClause,
 								  &byte_pct, &perbyte_cpu, &percall_cpu,
-								  &outin_ratio, &isImplicit, &isStrict,
-								  &volatility);
+								  &outin_ratio, &isStrict, &volatility);
 
 	interpret_AS_clause(languageOid, languageName, as_clause,
 						&prosrc_str, &probin_str);
@@ -517,7 +502,6 @@ CreateFunction(CreateFunctionStmt *stmt)
 					probin_str, /* converted to text later */
 					false,		/* not an aggregate */
 					security,
-					isImplicit,
 					isStrict,
 					volatility,
 					byte_pct,
@@ -639,3 +623,217 @@ RemoveFunctionById(Oid funcOid)
 		heap_close(relation, RowExclusiveLock);
 	}
 }
+
+
+
+/*
+ * CREATE CAST
+ */
+void
+CreateCast(CreateCastStmt *stmt)
+{
+	Oid			sourcetypeid;
+	Oid			targettypeid;
+	Oid			funcid;
+	HeapTuple	tuple;
+	Relation	relation;
+	Form_pg_proc procstruct;
+
+	Datum		values[Natts_pg_proc];
+	char		nulls[Natts_pg_proc];
+	int			i;
+
+	ObjectAddress myself,
+		referenced;
+
+	sourcetypeid = LookupTypeName(stmt->sourcetype);
+	if (!OidIsValid(sourcetypeid))
+		elog(ERROR, "source data type %s does not exist",
+			 TypeNameToString(stmt->sourcetype));
+
+	targettypeid = LookupTypeName(stmt->targettype);
+	if (!OidIsValid(targettypeid))
+		elog(ERROR, "target data type %s does not exist",
+			 TypeNameToString(stmt->targettype));
+
+	if (sourcetypeid == targettypeid)
+		elog(ERROR, "source data type and target data type are the same");
+
+	relation = heap_openr(CastRelationName, RowExclusiveLock);
+
+	tuple = SearchSysCache(CASTSOURCETARGET,
+						   ObjectIdGetDatum(sourcetypeid),
+						   ObjectIdGetDatum(targettypeid),
+						   0, 0);
+	if (HeapTupleIsValid(tuple))
+		elog(ERROR, "cast from data type %s to data type %s already exists",
+			 TypeNameToString(stmt->sourcetype),
+			 TypeNameToString(stmt->targettype));
+
+	if (stmt->func != NULL)
+	{
+		funcid = LookupFuncNameTypeNames(stmt->func->funcname, stmt->func->funcargs, false, "CreateCast");
+
+		if(!pg_proc_ownercheck(funcid, GetUserId()))
+			elog(ERROR, "permission denied");
+
+		tuple = SearchSysCache(PROCOID, ObjectIdGetDatum(funcid), 0, 0, 0);
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup of function %u failed", funcid);
+
+		procstruct = (Form_pg_proc) GETSTRUCT(tuple);
+		if (procstruct->pronargs != 1)
+			elog(ERROR, "cast function must take 1 argument");
+		if (procstruct->proargtypes[0] != sourcetypeid)
+			elog(ERROR, "argument of cast function must match source data type");
+		if (procstruct->prorettype != targettypeid)
+			elog(ERROR, "return data type of cast function must match target data type");
+		if (procstruct->provolatile != PROVOLATILE_IMMUTABLE)
+			elog(ERROR, "cast function must be immutable");
+		if (procstruct->proisagg)
+			elog(ERROR, "cast function must not be an aggregate function");
+		if (procstruct->proretset)
+			elog(ERROR, "cast function must be not return a set");
+
+		ReleaseSysCache(tuple);
+	}
+	else
+	{
+		/* indicates binary compatibility */
+		if (!pg_type_ownercheck(sourcetypeid, GetUserId())
+			|| !pg_type_ownercheck(targettypeid, GetUserId()))
+			elog(ERROR, "permission denied");
+		funcid = 0;
+	}
+
+	/* ready to go */
+	values[Anum_pg_cast_castsource-1] = ObjectIdGetDatum(sourcetypeid);
+	values[Anum_pg_cast_casttarget-1] = ObjectIdGetDatum(targettypeid);
+	values[Anum_pg_cast_castfunc-1] = ObjectIdGetDatum(funcid);
+	values[Anum_pg_cast_castimplicit-1] = BoolGetDatum(stmt->implicit);
+
+	for (i = 0; i < Natts_pg_cast; ++i)
+		nulls[i] = ' ';
+
+	tuple = heap_formtuple(RelationGetDescr(relation), values, nulls);
+	simple_heap_insert(relation, tuple);
+
+	if (RelationGetForm(relation)->relhasindex)
+	{
+		Relation	idescs[Num_pg_cast_indices];
+
+		CatalogOpenIndices(Num_pg_cast_indices, Name_pg_cast_indices, idescs);
+		CatalogIndexInsert(idescs, Num_pg_cast_indices, relation, tuple);
+		CatalogCloseIndices(Num_pg_cast_indices, idescs);
+	}
+
+	myself.classId = get_system_catalog_relid(CastRelationName);
+	myself.objectId = tuple->t_data->t_oid;
+	myself.objectSubId = 0;
+
+	/* dependency on source type */
+	referenced.classId = RelOid_pg_type;
+	referenced.objectId = sourcetypeid;
+	referenced.objectSubId = 0;
+	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+
+	/* dependency on target type */
+	referenced.classId = RelOid_pg_type;
+	referenced.objectId = targettypeid;
+	referenced.objectSubId = 0;
+	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+
+	/* dependency on function */
+	if (OidIsValid(funcid))
+	{
+		referenced.classId = RelOid_pg_proc;
+		referenced.objectId = funcid;
+		referenced.objectSubId = 0;
+		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+	}
+
+	heap_freetuple(tuple);
+	heap_close(relation, RowExclusiveLock);
+}
+
+
+
+/*
+ * DROP CAST
+ */
+void
+DropCast(DropCastStmt *stmt)
+{
+	Oid			sourcetypeid;
+	Oid			targettypeid;
+	HeapTuple	tuple;
+	Form_pg_cast caststruct;
+	ObjectAddress object;
+
+	sourcetypeid = LookupTypeName(stmt->sourcetype);
+	if (!OidIsValid(sourcetypeid))
+		elog(ERROR, "source data type %s does not exist",
+			 TypeNameToString(stmt->sourcetype));
+
+	targettypeid = LookupTypeName(stmt->targettype);
+	if (!OidIsValid(targettypeid))
+		elog(ERROR, "target data type %s does not exist",
+			 TypeNameToString(stmt->targettype));
+
+	tuple = SearchSysCache(CASTSOURCETARGET,
+						 ObjectIdGetDatum(sourcetypeid),
+						 ObjectIdGetDatum(targettypeid),
+						 0, 0);
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "cast from type %s to type %s does not exist",
+			 TypeNameToString(stmt->sourcetype),
+			 TypeNameToString(stmt->targettype));
+
+	/* Permission check */
+	caststruct = (Form_pg_cast) GETSTRUCT(tuple);
+	if (caststruct->castfunc != InvalidOid)
+	{
+		if(!pg_proc_ownercheck(caststruct->castfunc, GetUserId()))
+			elog(ERROR, "permission denied");
+	}
+	else
+	{
+		if (!pg_type_ownercheck(sourcetypeid, GetUserId())
+			|| !pg_type_ownercheck(targettypeid, GetUserId()))
+			elog(ERROR, "permission denied");
+	}
+
+	ReleaseSysCache(tuple);
+
+	/*
+	 * Do the deletion
+	 */
+	object.classId = get_system_catalog_relid(CastRelationName);
+	object.objectId = tuple->t_data->t_oid;
+	object.objectSubId = 0;
+
+	performDeletion(&object, stmt->behavior);
+}
+
+
+void
+DropCastById(Oid castOid)
+{
+	Relation	relation;
+	ScanKeyData scankey;
+	HeapScanDesc scan;
+	HeapTuple	tuple;
+
+	relation = heap_openr(CastRelationName, RowExclusiveLock);
+	ScanKeyEntryInitialize(&scankey, 0x0,
+						   ObjectIdAttributeNumber, F_OIDEQ,
+						   ObjectIdGetDatum(castOid));
+	scan = heap_beginscan(relation, SnapshotNow, 1, &scankey);
+	tuple = heap_getnext(scan, ForwardScanDirection);
+	if (HeapTupleIsValid(tuple))
+		simple_heap_delete(relation, &tuple->t_self);
+	else
+		elog(ERROR, "could not find tuple for cast %u", castOid);
+	heap_endscan(scan);
+	heap_close(relation, RowExclusiveLock);
+}

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.346 2002/07/18 17:14:19 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.347 2002/07/18 23:11:27 petere Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -135,13 +135,13 @@ static void doNegateFloat(Value *v);
 		AlterDatabaseSetStmt, AlterGroupStmt,
 		AlterTableStmt, AlterUserStmt, AlterUserSetStmt,
 		AnalyzeStmt, ClosePortalStmt, ClusterStmt, CommentStmt,
-		ConstraintsSetStmt, CopyStmt, CreateAsStmt,
+		ConstraintsSetStmt, CopyStmt, CreateAsStmt, CreateCastStmt,
 		CreateDomainStmt, CreateGroupStmt, CreatePLangStmt,
 		CreateSchemaStmt, CreateSeqStmt, CreateStmt,
 		CreateAssertStmt, CreateTrigStmt, CreateUserStmt,
 		CreatedbStmt, CursorStmt, DefineStmt, DeleteStmt,
 		DropGroupStmt, DropPLangStmt, DropStmt,
-		DropAssertStmt, DropTrigStmt, DropRuleStmt,
+		DropAssertStmt, DropTrigStmt, DropRuleStmt, DropCastStmt,
 		DropUserStmt, DropdbStmt, ExplainStmt, FetchStmt,
 		GrantStmt, IndexStmt, InsertStmt, ListenStmt, LoadStmt,
 		LockStmt, NotifyStmt, OptimizableStmt,
@@ -165,7 +165,7 @@ static void doNegateFloat(Value *v);
 %type <defelt>	createdb_opt_item, copy_opt_item
 
 %type <ival>	opt_lock, lock_type
-%type <boolean>	opt_force, opt_or_replace
+%type <boolean>	opt_force, opt_or_replace, opt_assignment
 
 %type <list>	user_list
 
@@ -346,7 +346,7 @@ static void doNegateFloat(Value *v);
 
 	HANDLER, HAVING, HOUR_P,
 
-	ILIKE, IMMEDIATE, IMMUTABLE, IMPLICIT, IN_P, INCREMENT,
+	ILIKE, IMMEDIATE, IMMUTABLE, IN_P, INCREMENT,
 	INDEX, INHERITS, INITIALLY, INNER_P, INOUT, INPUT,
 	INSENSITIVE, INSERT, INSTEAD, INT, INTEGER, INTERSECT,
 	INTERVAL, INTO, INVOKER, IS, ISNULL, ISOLATION,
@@ -475,6 +475,7 @@ stmt :
 			| CopyStmt
 			| CreateStmt
 			| CreateAsStmt
+			| CreateCastStmt
 			| CreateDomainStmt
 			| CreateFunctionStmt
 			| CreateSchemaStmt
@@ -489,6 +490,7 @@ stmt :
 			| DropStmt
 			| TruncateStmt
 			| CommentStmt
+			| DropCastStmt
 			| DropGroupStmt
 			| DropPLangStmt
 			| DropAssertStmt
@@ -2886,15 +2888,6 @@ RecipeStmt:  EXECUTE RECIPE recipe_name
  *						as <filename or code in language as appropriate>
  *						language <lang> [with parameters]
  *
- * CAST() form allowing all options from the CREATE FUNCTION form:
- *				create [or replace] cast (<type> as <type>)
- *						as <filename or code in language as appropriate>
- *						language <lang> [with parameters]
- *
- * SQL99 CAST() form (requires a function to be previously defined):
- *				create [or replace] cast (<type> as <type>)
- *						with function fname (<type>) [as assignment]
- *
  *****************************************************************************/
 
 CreateFunctionStmt:
@@ -2910,63 +2903,6 @@ CreateFunctionStmt:
 					n->withClause = $9;
 					$$ = (Node *)n;
 				}
-		/* CREATE CAST SQL99 standard form */
-		| CREATE opt_or_replace CAST '(' func_type AS func_type ')'
-			WITH FUNCTION func_name func_args opt_assignment opt_definition
-				{
-					CreateFunctionStmt *n;
-					char buf[256];
-					n = makeNode(CreateFunctionStmt);
-					n->replace = $2;
-					n->funcname = $7->names;
-					n->argTypes = makeList1($5);
-					n->returnType = $7;
-					/* expand this into a string of SQL language */
-					strcpy(buf, "select ");
-					strcat(buf, ((Value *)lfirst($11))->val.str);
-					strcat(buf, "($1)");
-					n->options = lappend($14, makeDefElem("as", (Node *)makeList1(makeString(pstrdup(buf)))));
-					/* make sure that this will allow implicit casting */
-					n->options = lappend(n->options,
-										 makeDefElem("implicit", (Node *)makeInteger(TRUE)));
-					/* and mention that this is SQL language */
-					n->options = lappend(n->options,
-										 makeDefElem("language", (Node *)makeString(pstrdup("sql"))));
-					$$ = (Node *)n;
-				}
-		/* CREATE CAST SQL99 minimally variant form */
-		| CREATE opt_or_replace CAST '(' func_type AS func_type ')'
-			WITH FUNCTION func_name func_args AS Sconst opt_definition
-				{
-					CreateFunctionStmt *n;
-					n = makeNode(CreateFunctionStmt);
-					n->replace = $2;
-					n->funcname = $7->names;
-					n->argTypes = makeList1($5);
-					n->returnType = $7;
-					n->options = lappend($15, makeDefElem("as", (Node *)lcons(makeList1(makeString($14)), $11)));
-					/* make sure that this will allow implicit casting */
-					n->options = lappend(n->options,
-										 makeDefElem("implicit", (Node *)makeInteger(TRUE)));
-					n->options = lappend(n->options,
-										 makeDefElem("language", (Node *)makeString(pstrdup("c"))));
-					$$ = (Node *)n;
-				}
-		/* CREATE CAST with mostly CREATE FUNCTION clauses */
-		| CREATE opt_or_replace CAST '(' func_type AS func_type ')'
-			createfunc_opt_list opt_definition
-				{
-					CreateFunctionStmt *n;
-					n = makeNode(CreateFunctionStmt);
-					n->replace = $2;
-					n->funcname = $7->names;
-					n->argTypes = makeList1($5);
-					n->returnType = $7;
-					/* make sure that this will allow implicit casting */
-					n->options = lappend($9, makeDefElem("implicit", (Node *)makeInteger(TRUE)));
-					n->withClause = $10;
-					$$ = (Node *)n;
-				}
 		;
 
 opt_or_replace:
@@ -3090,10 +3026,6 @@ createfunc_opt_item:
 				{
 					$$ = makeDefElem("security", (Node *)makeInteger(FALSE));
 				}
-			| IMPLICIT CAST
-				{
-					$$ = makeDefElem("implicit", (Node *)makeInteger(TRUE));
-				}
 		;
 
 func_as:	Sconst						{ $$ = makeList1(makeString($1)); }
@@ -3108,10 +3040,6 @@ opt_definition:
 			| /*EMPTY*/								{ $$ = NIL; }
 		;
 
-opt_assignment:  AS ASSIGNMENT					{}
-		| /*EMPTY*/								{}
-		;
-
 
 /*****************************************************************************
  *
@@ -3132,14 +3060,6 @@ RemoveFuncStmt:
 					n->behavior = $5;
 					$$ = (Node *)n;
 				}
-		| DROP CAST '(' func_type AS func_type ')' opt_drop_behavior
-				{
-					RemoveFuncStmt *n = makeNode(RemoveFuncStmt);
-					n->funcname = $6->names;
-					n->args = makeList1($4);
-					n->behavior = $8;
-					$$ = (Node *)n;
-				}
 		;
 
 RemoveAggrStmt:
@@ -3190,6 +3110,49 @@ any_operator:
 		;
 
 
+/*****************************************************************************
+ *
+ *		CREATE CAST / DROP CAST
+ *
+ *****************************************************************************/
+
+CreateCastStmt: CREATE CAST '(' ConstTypename AS ConstTypename ')'
+					WITH FUNCTION function_with_argtypes opt_assignment
+				{
+					CreateCastStmt *n = makeNode(CreateCastStmt);
+					n->sourcetype = $4;
+					n->targettype = $6;
+					n->func = (FuncWithArgs *) $10;
+					n->implicit = $11;
+					$$ = (Node *)n;
+				}
+			| CREATE CAST '(' ConstTypename AS ConstTypename ')'
+					WITHOUT FUNCTION opt_assignment
+				{
+					CreateCastStmt *n = makeNode(CreateCastStmt);
+					n->sourcetype = $4;
+					n->targettype = $6;
+					n->func = NULL;
+					n->implicit = $10;
+					$$ = (Node *)n;
+				}
+
+opt_assignment:  AS ASSIGNMENT					{ $$ = TRUE; }
+		| /*EMPTY*/								{ $$ = FALSE; }
+		;
+
+
+DropCastStmt: DROP CAST '(' ConstTypename AS ConstTypename ')' opt_drop_behavior
+				{
+					DropCastStmt *n = makeNode(DropCastStmt);
+					n->sourcetype = $4;
+					n->targettype = $6;
+					n->behavior = $8;
+					$$ = (Node *)n;
+				}
+
+
+
 /*****************************************************************************
  *
  *		QUERY:
@@ -6701,7 +6664,6 @@ unreserved_keyword:
 			| HOUR_P
 			| IMMEDIATE
 			| IMMUTABLE
-			| IMPLICIT
 			| INCREMENT
 			| INDEX
 			| INHERITS

src/backend/parser/keywords.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.121 2002/07/18 17:14:19 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.122 2002/07/18 23:11:28 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -142,7 +142,6 @@ static const ScanKeyword ScanKeywords[] = {
 	{"ilike", ILIKE},
 	{"immediate", IMMEDIATE},
 	{"immutable", IMMUTABLE},
-	{"implicit", IMPLICIT},
 	{"in", IN_P},
 	{"increment", INCREMENT},
 	{"index", INDEX},

src/backend/parser/parse_coerce.c

@@ -8,12 +8,13 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.77 2002/07/09 13:52:14 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.78 2002/07/18 23:11:28 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
+#include "catalog/pg_cast.h"
 #include "catalog/pg_proc.h"
 #include "nodes/makefuncs.h"
 #include "optimizer/clauses.h"
@@ -31,8 +32,9 @@ Oid			PromoteTypeToNext(Oid inType);
 
 static Oid	PreferredType(CATEGORY category, Oid type);
 static Node *build_func_call(Oid funcid, Oid rettype, List *args);
-static Oid	find_coercion_function(Oid targetTypeId, Oid inputTypeId,
-								   Oid secondArgType, bool isExplicit);
+static Oid	find_coercion_function(Oid targetTypeId, Oid sourceTypeId,
+								   bool isExplicit);
+static Oid	find_typmod_coercion_function(Oid typeId);
 static Node	*TypeConstraints(Node *arg, Oid typeId);
 
 /* coerce_type()
@@ -142,7 +144,6 @@ coerce_type(ParseState *pstate, Node *node, Oid inputTypeId,
 
 		funcId = find_coercion_function(baseTypeId,
 										getBaseType(inputTypeId),
-										InvalidOid,
 										isExplicit);
 		if (!OidIsValid(funcId))
 			elog(ERROR, "coerce_type: no conversion function from '%s' to '%s'",
@@ -258,7 +259,6 @@ can_coerce_type(int nargs, Oid *input_typeids, Oid *func_typeids,
 		 */
 		funcId = find_coercion_function(getBaseType(targetTypeId),
 										getBaseType(inputTypeId),
-										InvalidOid,
 										isExplicit);
 		if (!OidIsValid(funcId))
 			return false;
@@ -312,8 +312,7 @@ coerce_type_typmod(ParseState *pstate, Node *node,
 	if (atttypmod < 0 || atttypmod == exprTypmod(node))
 		return node;
 
-	/* Note this is always implicit coercion */
-	funcId = find_coercion_function(baseTypeId, baseTypeId, INT4OID, false);
+	funcId = find_typmod_coercion_function(baseTypeId);
 	if (OidIsValid(funcId))
 	{
 		Const	   *cons;
@@ -621,21 +620,25 @@ TypeCategory(Oid inType)
 static bool
 DirectlyBinaryCompatible(Oid type1, Oid type2)
 {
+	HeapTuple	tuple;
+	bool		result;
+
 	if (type1 == type2)
 		return true;
-	if (TypeIsTextGroup(type1) && TypeIsTextGroup(type2))
-		return true;
-	if (TypeIsInt4GroupA(type1) && TypeIsInt4GroupA(type2))
-		return true;
-	if (TypeIsInt4GroupB(type1) && TypeIsInt4GroupB(type2))
-		return true;
-	if (TypeIsInt4GroupC(type1) && TypeIsInt4GroupC(type2))
-		return true;
-	if (TypeIsInetGroup(type1) && TypeIsInetGroup(type2))
-		return true;
-	if (TypeIsBitGroup(type1) && TypeIsBitGroup(type2))
-		return true;
-	return false;
+
+	tuple = SearchSysCache(CASTSOURCETARGET, type1, type2, 0, 0);
+	if (HeapTupleIsValid(tuple))
+	{
+		Form_pg_cast caststruct;
+
+		caststruct = (Form_pg_cast) GETSTRUCT(tuple);
+		result = caststruct->castfunc == InvalidOid && caststruct->castimplicit;
+		ReleaseSysCache(tuple);
+	}
+	else
+		result = false;
+
+	return result;
 }
 
 
@@ -750,34 +753,51 @@ PreferredType(CATEGORY category, Oid type)
  * If a function is found, return its pg_proc OID; else return InvalidOid.
  */
 static Oid
-find_coercion_function(Oid targetTypeId, Oid inputTypeId, Oid secondArgType,
-					   bool isExplicit)
+find_coercion_function(Oid targetTypeId, Oid sourceTypeId, bool isExplicit)
+{
+	Oid			funcid = InvalidOid;
+	HeapTuple	tuple;
+
+	tuple = SearchSysCache(CASTSOURCETARGET,
+						   ObjectIdGetDatum(sourceTypeId),
+						   ObjectIdGetDatum(targetTypeId),
+						   0, 0);
+
+	if (HeapTupleIsValid(tuple))
+	{
+		Form_pg_cast cform = (Form_pg_cast) GETSTRUCT(tuple);
+
+		if (isExplicit || cform->castimplicit)
+			funcid = cform->castfunc;
+
+		ReleaseSysCache(tuple);
+	}
+
+	return funcid;
+}
+
+
+static Oid
+find_typmod_coercion_function(Oid typeId)
 {
 	Oid			funcid = InvalidOid;
 	Type		targetType;
 	char	   *typname;
 	Oid			typnamespace;
 	Oid			oid_array[FUNC_MAX_ARGS];
-	int			nargs;
 	HeapTuple	ftup;
 
-	targetType = typeidType(targetTypeId);
+	targetType = typeidType(typeId);
 	typname = NameStr(((Form_pg_type) GETSTRUCT(targetType))->typname);
 	typnamespace = ((Form_pg_type) GETSTRUCT(targetType))->typnamespace;
 
 	MemSet(oid_array, 0, FUNC_MAX_ARGS * sizeof(Oid));
-	oid_array[0] = inputTypeId;
-	if (OidIsValid(secondArgType))
-	{
-		oid_array[1] = secondArgType;
-		nargs = 2;
-	}
-	else
-		nargs = 1;
+	oid_array[0] = typeId;
+	oid_array[1] = INT4OID;
 
 	ftup = SearchSysCache(PROCNAMENSP,
 						  CStringGetDatum(typname),
-						  Int16GetDatum(nargs),
+						  Int16GetDatum(2),
 						  PointerGetDatum(oid_array),
 						  ObjectIdGetDatum(typnamespace));
 	if (HeapTupleIsValid(ftup))
@@ -785,15 +805,11 @@ find_coercion_function(Oid targetTypeId, Oid inputTypeId, Oid secondArgType,
 		Form_pg_proc pform = (Form_pg_proc) GETSTRUCT(ftup);
 
 		/* Make sure the function's result type is as expected */
-		if (pform->prorettype == targetTypeId && !pform->proretset &&
+		if (pform->prorettype == typeId && !pform->proretset &&
 			!pform->proisagg)
 		{
-			/* If needed, make sure it can be invoked implicitly */
-			if (isExplicit || pform->proimplicit)
-			{
-				/* Okay to use it */
-				funcid = ftup->t_data->t_oid;
-			}
+			/* Okay to use it */
+			funcid = ftup->t_data->t_oid;
 		}
 		ReleaseSysCache(ftup);
 	}

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.271 2002/07/18 16:47:25 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.272 2002/07/18 23:11:28 petere Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -1693,7 +1693,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.271 $ $Date: 2002/07/18 16:47:25 $\n");
+		puts("$Revision: 1.272 $ $Date: 2002/07/18 23:11:28 $\n");
 	}
 
 	/*
@@ -2444,6 +2444,14 @@ CreateCommandTag(Node *parsetree)
 			tag = "CREATE CONVERSION";
 			break;
 
+		case T_CreateCastStmt:
+			tag = "CREATE CAST";
+			break;
+
+		case T_DropCastStmt:
+			tag = "DROP CAST";
+			break;
+
 		default:
 			elog(LOG, "CreateCommandTag: unknown parse node type %d",
 				 nodeTag(parsetree));

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.163 2002/07/18 16:47:25 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.164 2002/07/18 23:11:28 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -829,6 +829,14 @@ ProcessUtility(Node *parsetree,
 			}
 			break;
 
+		case T_CreateCastStmt:
+			CreateCast((CreateCastStmt *) parsetree);
+			break;
+
+		case T_DropCastStmt:
+			DropCast((DropCastStmt *) parsetree);
+			break;
+
 		default:
 			elog(ERROR, "ProcessUtility: command #%d unsupported",
 				 nodeTag(parsetree));

src/backend/utils/adt/ruleutils.c

@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.111 2002/07/18 17:14:20 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.112 2002/07/18 23:11:28 petere Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -43,6 +43,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_cast.h"
 #include "catalog/pg_index.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
@@ -2048,9 +2049,9 @@ get_agg_expr(Aggref *aggref, deparse_context *context)
  *		Strip any type coercions at the top of the given expression tree,
  *		as long as they are coercions to the given datatype.
  *
- * A RelabelType node is always a type coercion.  A function call is also
- * considered a type coercion if it has one argument and the function name
- * is the same as the (internal) name of its result type.
+ * A RelabelType node is always a type coercion.  A function call is
+ * also considered a type coercion if it has one argument and there is
+ * a cast declared that uses it.
  *
  * XXX It'd be better if the parsetree retained some explicit indication
  * of the coercion, so we didn't need these heuristics.
@@ -2069,9 +2070,9 @@ strip_type_coercion(Node *expr, Oid resultType)
 	{
 		Func	   *func;
 		HeapTuple	procTuple;
-		HeapTuple	typeTuple;
+		HeapTuple	castTuple;
 		Form_pg_proc procStruct;
-		Form_pg_type typeStruct;
+		Form_pg_cast castStruct;
 
 		func = (Func *) (((Expr *) expr)->oper);
 		Assert(IsA(func, Func));
@@ -2085,33 +2086,33 @@ strip_type_coercion(Node *expr, Oid resultType)
 			elog(ERROR, "cache lookup for proc %u failed", func->funcid);
 		procStruct = (Form_pg_proc) GETSTRUCT(procTuple);
 		/* Double-check func has one arg and correct result type */
-		/* Also, it must be an implicit coercion function */
 		if (procStruct->pronargs != 1 ||
-			procStruct->prorettype != resultType ||
-			!procStruct->proimplicit)
+			procStruct->prorettype != resultType)
 		{
 			ReleaseSysCache(procTuple);
 			return expr;
 		}
-		/* See if function has same name/namespace as its result type */
-		typeTuple = SearchSysCache(TYPEOID,
-								ObjectIdGetDatum(procStruct->prorettype),
-								   0, 0, 0);
-		if (!HeapTupleIsValid(typeTuple))
-			elog(ERROR, "cache lookup for type %u failed",
-				 procStruct->prorettype);
-		typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);
-		if (strcmp(NameStr(procStruct->proname),
-				   NameStr(typeStruct->typname)) != 0 ||
-			procStruct->pronamespace != typeStruct->typnamespace)
+		/* See if function has is actually declared as a cast */
+		castTuple = SearchSysCache(CASTSOURCETARGET,
+								   ObjectIdGetDatum(procStruct->proargtypes[0]),
+								   ObjectIdGetDatum(procStruct->prorettype),
+								   0, 0);
+		if (!HeapTupleIsValid(castTuple))
 		{
 			ReleaseSysCache(procTuple);
-			ReleaseSysCache(typeTuple);
+			return expr;
+		}
+		/* It must also be an implicit cast. */
+		castStruct = (Form_pg_cast) GETSTRUCT(castTuple);
+		if (!castStruct->castimplicit)
+		{
+			ReleaseSysCache(procTuple);
+			ReleaseSysCache(castTuple);
 			return expr;
 		}
 		/* Okay, it is indeed a type-coercion function */
 		ReleaseSysCache(procTuple);
-		ReleaseSysCache(typeTuple);
+		ReleaseSysCache(castTuple);
 		return strip_type_coercion(lfirst(((Expr *) expr)->args), resultType);
 	}
 

src/backend/utils/adt/sets.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.46 2002/06/20 20:29:38 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.47 2002/07/18 23:11:29 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,7 +63,6 @@ SetDefine(char *querystr, Oid elemType)
 							 fileName,	/* probin */
 							 false,		/* not aggregate */
 							 false,		/* security invoker */
-							 false,		/* not implicit coercion */
 							 false,		/* isStrict (irrelevant, no args) */
 							 PROVOLATILE_VOLATILE,	/* assume unsafe */
 							 100,		/* byte_pct */

src/backend/utils/cache/syscache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.81 2002/07/11 07:39:27 ishii Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.82 2002/07/18 23:11:29 petere Exp $
  *
  * NOTES
  *	  These routines allow the parser/planner/executor to perform
@@ -28,6 +28,7 @@
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_amop.h"
 #include "catalog/pg_amproc.h"
+#include "catalog/pg_cast.h"
 #include "catalog/pg_conversion.h"
 #include "catalog/pg_group.h"
 #include "catalog/pg_index.h"
@@ -174,6 +175,17 @@ static const struct cachedesc cacheinfo[] = {
 			0,
 			0
 	}},
+	{
+		CastRelationName,			/* CASTSOURCETARGET */
+		CastSourceTargetIndex,
+		0,
+		2,
+		{
+			Anum_pg_cast_castsource,
+			Anum_pg_cast_casttarget,
+			0,
+			0
+	}},
 	{OperatorClassRelationName, /* CLAAMNAMENSP */
 		OpclassAmNameNspIndex,
 		0,