This patch adds support for %TYPE in CREATE FUNCTION argument and return

types.  This version has an elog() to remind the user the type
resolution is not dynamic.

Ian Lance Taylor

doc/src/sgml/ref/create_function.sgml

 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.23 2001/05/19 09:01:10 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_function.sgml,v 1.24 2001/06/04 23:27:23 momjian Exp $
 -->
 
 <refentry id="SQL-CREATEFUNCTION">
@@ -55,10 +55,16 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceab
      <listitem>
       <para>
        The data type(s) of the function's arguments, if any.  The
-       input types may be base or complex types, or
-       <literal>opaque</literal>.  <literal>Opaque</literal> indicates
+       input types may be base or complex types,
+       <literal>opaque</literal>, or the same as the type of an
+       existing column.  <literal>Opaque</literal> indicates
        that the function accepts arguments of a non-SQL type such as
        <type>char *</type>.
+	The type of a column is indicated using <replaceable
+	class="parameter">tablename</replaceable>.<replaceable
+	class="parameter">columnname</replaceable><literal>%TYPE</literal>;
+	using this can sometimes help make a function independent from
+	changes to the definition of a table.
       </para>
      </listitem>
     </varlistentry>
@@ -69,8 +75,10 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceab
      <listitem>
       <para>
        The return data type.  The output type may be specified as a
-       base type, complex type, <literal>setof</literal> type, or
-       <literal>opaque</literal>.  The <literal>setof</literal>
+       base type, complex type, <literal>setof</literal> type,
+       <literal>opaque</literal>, or the same as the type of an
+       existing column.
+       The <literal>setof</literal>
        modifier indicates that the function will return a set of
        items, rather than a single item.  Functions with a declared
        return type of <literal>opaque</literal> do not return a value.

src/backend/parser/analyze.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.188 2001/06/04 16:17:30 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.189 2001/06/04 23:27:23 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,6 +29,7 @@
 #include "parser/parse_relation.h"
 #include "parser/parse_target.h"
 #include "parser/parse_type.h"
+#include "parser/parse_expr.h"
 #include "rewrite/rewriteManip.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
@@ -51,7 +52,10 @@ static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
 static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
 static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
 static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);
+static Node *transformTypeRefs(ParseState *pstate, Node *stmt);
 
+static void transformTypeRefsList(ParseState *pstate, List *l);
+static void transformTypeRef(ParseState *pstate, TypeName *tn);
 static List *getSetColTypes(ParseState *pstate, Node *node);
 static void transformForUpdate(Query *qry, List *forUpdate);
 static void transformFkeyGetPrimaryKey(FkConstraint *fkconstraint, Oid *pktypoid);
@@ -232,6 +236,17 @@ transformStmt(ParseState *pstate, Node *parseTree)
 											   (SelectStmt *) parseTree);
 			break;
 
+			/*
+			 * Convert use of %TYPE in statements where it is permitted.
+			 */
+		case T_ProcedureStmt:
+		case T_CommentStmt:
+		case T_RemoveFuncStmt:
+		case T_DefineStmt:
+			result = makeNode(Query);
+			result->commandType = CMD_UTILITY;
+			result->utilityStmt = transformTypeRefs(pstate, parseTree);
+			break;
 
 		default:
 
@@ -2701,6 +2716,107 @@ transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
 	return qry;
 }
 
+/* 
+ * Transform uses of %TYPE in a statement.
+ */
+static Node *
+transformTypeRefs(ParseState *pstate, Node *stmt)
+{
+	switch (nodeTag(stmt))
+	{
+		case T_ProcedureStmt:
+		{
+			ProcedureStmt  *ps = (ProcedureStmt *) stmt;
+
+			transformTypeRefsList(pstate, ps->argTypes);
+			transformTypeRef(pstate, (TypeName *) ps->returnType);
+			transformTypeRefsList(pstate, ps->withClause);
+		}
+		break;
+
+		case T_CommentStmt:
+		{
+			CommentStmt	   *cs = (CommentStmt *) stmt;
+
+			transformTypeRefsList(pstate, cs->objlist);
+		}
+		break;
+
+		case T_RemoveFuncStmt:
+		{
+			RemoveFuncStmt *rs = (RemoveFuncStmt *) stmt;
+
+			transformTypeRefsList(pstate, rs->args);
+		}
+		break;
+
+		case T_DefineStmt:
+		{
+			DefineStmt *ds = (DefineStmt *) stmt;
+			List	   *ele;
+
+			foreach(ele, ds->definition)
+			{
+				DefElem	   *de = (DefElem *) lfirst(ele);
+
+				if (de->arg != NULL
+					&& IsA(de->arg, TypeName))
+				{
+					transformTypeRef(pstate, (TypeName *) de->arg);
+				}
+			}
+		}
+		break;
+
+		default:
+			elog(ERROR, "Unsupported type %d in transformTypeRefs",
+				 nodeTag(stmt));
+			break;
+	}
+
+	return stmt;
+}
+
+/*
+ * Transform uses of %TYPE in a list.
+ */
+static void
+transformTypeRefsList(ParseState *pstate, List *l)
+{
+	List	   *ele;
+
+	foreach(ele, l)
+	{
+		if (IsA(lfirst(ele), TypeName))
+			transformTypeRef(pstate, (TypeName *) lfirst(ele));
+	}
+}
+
+/*
+ * Transform a TypeName to not use %TYPE.
+ */
+static void
+transformTypeRef(ParseState *pstate, TypeName *tn)
+{
+	Attr   *att;
+	Node   *n;
+	Var	   *v;
+	char   *tyn;
+
+	if (tn->attrname == NULL)
+		return;
+	att = makeAttr(tn->name, tn->attrname);
+	n = transformExpr(pstate, (Node *) att, EXPR_COLUMN_FIRST);
+	if (! IsA(n, Var))
+		elog(ERROR, "unsupported expression in %%TYPE");
+	v = (Var *) n;
+	tyn = typeidTypeName(v->vartype);
+	elog(NOTICE, "%s.%s%%TYPE converted to %s", tn->name, tn->attrname, tyn);
+	tn->name = tyn;
+	tn->typmod = v->vartypmod;
+	tn->attrname = NULL;
+}
+
 /* exported so planner can check again after rewriting, query pullup, etc */
 void
 CheckSelectForUpdate(Query *qry)

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.227 2001/05/27 09:59:29 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.228 2001/06/04 23:27:23 momjian Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -192,7 +192,7 @@ static void doNegateFloat(Value *v);
 		def_list, opt_indirection, group_clause, TriggerFuncArgs,
 		select_limit, opt_select_limit
 
-%type <typnam>	func_arg, func_return, aggr_argtype
+%type <typnam>	func_arg, func_return, func_type, aggr_argtype
 
 %type <boolean>	opt_arg, TriggerForOpt, TriggerForType, OptTemp
 
@@ -2490,7 +2490,7 @@ func_args_list:  func_arg
 				{	$$ = lappend($1, $3); }
 		;
 
-func_arg:  opt_arg Typename
+func_arg:  opt_arg func_type
 				{
 					/* We can catch over-specified arguments here if we want to,
 					 * but for now better to silently swallow typmod, etc.
@@ -2498,7 +2498,7 @@ func_arg:  opt_arg Typename
 					 */
 					$$ = $2;
 				}
-		| Typename
+		| func_type
 				{
 					$$ = $1;
 				}
@@ -2526,7 +2526,7 @@ func_as: Sconst
 				{ 	$$ = makeList2(makeString($1), makeString($3)); }
 		;
 
-func_return:  Typename
+func_return:  func_type
 				{
 					/* We can catch over-specified arguments here if we want to,
 					 * but for now better to silently swallow typmod, etc.
@@ -2536,6 +2536,18 @@ func_return:  Typename
 				}
 		;
 
+func_type:	Typename
+				{
+					$$ = $1;
+				}
+		| IDENT '.' ColId '%' TYPE_P
+				{
+					$$ = makeNode(TypeName);
+					$$->name = $1;
+					$$->typmod = -1;
+					$$->attrname = $3;
+				}
+		;
 
 /*****************************************************************************
  *

src/backend/parser/parse_expr.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.96 2001/05/21 18:42:08 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.97 2001/06/04 23:27:23 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -942,6 +942,7 @@ parser_typecast_expression(ParseState *pstate,
 char *
 TypeNameToInternalName(TypeName *typename)
 {
+	Assert(typename->attrname == NULL);
 	if (typename->arrayBounds != NIL)
 	{
 

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.129 2001/05/21 18:42:08 momjian Exp $
+ * $Id: parsenodes.h,v 1.130 2001/06/04 23:27:23 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -951,6 +951,7 @@ typedef struct TypeName
 	bool		setof;			/* is a set? */
 	int32		typmod;			/* type modifier */
 	List	   *arrayBounds;	/* array bounds */
+	char	   *attrname;		/* field name when using %TYPE */
 } TypeName;
 
 /*

src/test/regress/input/create_function_2.source

@@ -13,6 +13,12 @@ CREATE FUNCTION hobby_construct(text, text)
    LANGUAGE 'sql';
 
 
+CREATE FUNCTION hobbies_by_name(hobbies_r.name%TYPE)
+   RETURNS hobbies_r.person%TYPE
+   AS 'select person from hobbies_r where name = $1'
+   LANGUAGE 'sql';
+
+
 CREATE FUNCTION equipment(hobbies_r)
    RETURNS setof equipment_r
    AS 'select * from equipment_r where hobby = $1.name'

src/test/regress/input/misc.source

@@ -214,6 +214,7 @@ SELECT user_relns() AS user_relns
 
 --SELECT name(equipment(hobby_construct(text 'skywalking', text 'mer'))) AS equip_name;
 
+SELECT hobbies_by_name('basketball');
 
 --
 -- check that old-style C functions work properly with TOASTed values

src/test/regress/output/create_function_2.source

@@ -9,6 +9,12 @@ CREATE FUNCTION hobby_construct(text, text)
    RETURNS hobbies_r
    AS 'select $1 as name, $2 as hobby'
    LANGUAGE 'sql';
+CREATE FUNCTION hobbies_by_name(hobbies_r.name%TYPE)
+   RETURNS hobbies_r.person%TYPE
+   AS 'select person from hobbies_r where name = $1'
+   LANGUAGE 'sql';
+NOTICE:  hobbies_r.name%TYPE converted to text
+NOTICE:  hobbies_r.person%TYPE converted to text
 CREATE FUNCTION equipment(hobbies_r)
    RETURNS setof equipment_r
    AS 'select * from equipment_r where hobby = $1.name'

src/test/regress/output/misc.source

@@ -656,6 +656,12 @@ SELECT user_relns() AS user_relns
 (90 rows)
 
 --SELECT name(equipment(hobby_construct(text 'skywalking', text 'mer'))) AS equip_name;
+SELECT hobbies_by_name('basketball');
+ hobbies_by_name 
+-----------------
+ joe
+(1 row)
+
 --
 -- check that old-style C functions work properly with TOASTed values
 --