the following little patch adds array references to query

    parameters. With it applied a function like

    CREATE FUNCTION getname(oid8, int4) RETURNS name AS
        'SELECT typname FROM pg_type WHERE oid = $1[$2]'
        LANGUAGE 'sql';

    is possible. Mainly I need this to enable array references in
    expressions for PL/pgSQL. Complete regression test ran O.K.

Jan

src/backend/parser/gram.y

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.33 1998/09/30 05:47:56 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.34 1998/10/02 16:23:04 momjian Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -4598,10 +4598,11 @@ AexprConst:  Iconst
 				}
 		;
 
-ParamNo:  PARAM
+ParamNo:  PARAM opt_indirection
 				{
 					$$ = makeNode(ParamNo);
 					$$->number = $1;
+					$$->indirection = $2;
 				}
 		;
 

src/backend/parser/parse_expr.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.35 1998/10/01 22:51:20 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_expr.c,v 1.36 1998/10/02 16:23:05 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -122,7 +122,39 @@ transformExpr(ParseState *pstate, Node *expr, int precedence)
 				param->paramtype = (Oid) toid;
 				param->param_tlist = (List *) NULL;
 
-				result = (Node *) param;
+				if (pno->indirection != NIL)
+				{
+					List	   *idx = pno->indirection;
+
+					while (idx != NIL)
+					{
+						A_Indices  *ai = (A_Indices *) lfirst(idx);
+						Node	   *lexpr = NULL,
+								   *uexpr;
+
+						uexpr = transformExpr(pstate, ai->uidx, precedence);	/* must exists */
+						if (exprType(uexpr) != INT4OID)
+							elog(ERROR, "array index expressions must be int4's");
+						if (ai->lidx != NULL)
+						{
+							lexpr = transformExpr(pstate, ai->lidx, precedence);
+							if (exprType(lexpr) != INT4OID)
+								elog(ERROR, "array index expressions must be int4's");
+						}
+						ai->lidx = lexpr;
+						ai->uidx = uexpr;
+
+						/*
+						 * note we reuse the list of indices, make sure we
+						 * don't free them! Otherwise, make a new list
+						 * here
+						 */
+						idx = lnext(idx);
+					}
+					result = (Node *) make_array_ref((Node *)param, pno->indirection);
+				}
+				else
+					result = (Node *) param;
 				break;
 			}
 		case T_A_Expr:

src/include/nodes/parsenodes.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.59 1998/09/01 04:36:43 momjian Exp $
+ * $Id: parsenodes.h,v 1.60 1998/10/02 16:23:07 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -667,6 +667,7 @@ typedef struct ParamNo
 	NodeTag		type;
 	int			number;			/* the number of the parameter */
 	TypeName   *typename;		/* the typecast */
+	List	   *indirection;	/* array references */
 } ParamNo;
 
 /*