Re: proposal - plpgsql - support standard syntax for named arguments for cursors

[Pavel Stehule]

Hi

so 8. 2. 2025 v 22:25 odesílatel Tom Lane <t...@sss.pgh.pa.us> napsal:

> Pavel Stehule <pavel.steh...@gmail.com> writes:
> > so 8. 2. 2025 v 20:25 odesílatel Tom Lane <t...@sss.pgh.pa.us> napsal:
> >> Is there any reason to think that that's actually in the standard?
>
> > I think the possibility to use named arguments in OPEN statements is a
> > PostgreSQL proprietary feature.
> > And usage of cursors in PL/pgSQL is based on PL/SQL (not on SQL/PSM from
> > standard), but named
> > arguments for cursor is PostgreSQL proprietary feature and the syntax
> based
> > on usage `:=` is our
> > proprietary too.
>
> Hmm ... yeah, it's not in SQL/PSM, but looking at PL/SQL:
>
>
> https://docs.oracle.com/en/database/oracle/oracle-database/19/lnpls/OPEN-statement.html
>
> I see
>
>     You can specify actual cursor parameters with either
>     positional notation or named notation. For information about
>     these notations, see "Positional, Named, and Mixed Notation
>     for Actual Parameters".
>
> and that link blesses the use of "name => value" (and not ":=").
> So agreed, we should adjust this.
>
> Is there a reason we need a whole new test case instead of
> tweaking one of the existing ones?
>
>
I changed regress tests like you proposed

Regards

Pavel


>                         regards, tom lane
>

From 938bd5007b62c854e423b696ac42c680fa28178e Mon Sep 17 00:00:00 2001
From: "ok...@github.com" <pavel.steh...@gmail.com>
Date: Sat, 8 Feb 2025 07:45:58 +0100
Subject: [PATCH] allow to use standard syntax for named arguments for plpgsql
 cursor arguments

---
 doc/src/sgml/plpgsql.sgml             |  3 ++-
 src/pl/plpgsql/src/pl_gram.y          | 13 ++++++++-----
 src/test/regress/expected/plpgsql.out |  3 ++-
 src/test/regress/sql/plpgsql.sql      |  3 ++-
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index 78e4983139b..60af57712b7 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -3317,7 +3317,7 @@ OPEN curs1 FOR EXECUTE format('SELECT * FROM %I WHERE col1 = $1',tabname) USING
      <title>Opening a Bound Cursor</title>
 
 <synopsis>
-OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <optional> <replaceable>argument_name</replaceable> := </optional> <replaceable>argument_value</replaceable> <optional>, ...</optional> ) </optional>;
+OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <optional> <replaceable>argument_name</replaceable> { := | => } </optional> <replaceable>argument_value</replaceable> <optional>, ...</optional> ) </optional>;
 </synopsis>
 
          <para>
@@ -3352,6 +3352,7 @@ OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <optional> <replace
 OPEN curs2;
 OPEN curs3(42);
 OPEN curs3(key := 42);
+OPEN curs3(Key => 42);
 </programlisting>
          </para>
 
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index 64d2c362bf9..618a97b64f2 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -3911,9 +3911,12 @@ read_cursor_args(PLpgSQL_var *cursor, int until, YYSTYPE *yylvalp, YYLTYPE *yyll
 					tok2;
 		int			arglocation;
 
-		/* Check if it's a named parameter: "param := value" */
+		/*
+		 * Check if it's a named parameter: "param := value"
+		 * or "param => value"
+		 */
 		plpgsql_peek2(&tok1, &tok2, &arglocation, NULL, yyscanner);
-		if (tok1 == IDENT && tok2 == COLON_EQUALS)
+		if (tok1 == IDENT && (tok2 == COLON_EQUALS || tok2 == EQUALS_GREATER))
 		{
 			char	   *argname;
 			IdentifierLookup save_IdentifierLookup;
@@ -3939,11 +3942,11 @@ read_cursor_args(PLpgSQL_var *cursor, int until, YYSTYPE *yylvalp, YYLTYPE *yyll
 						 parser_errposition(*yyllocp)));
 
 			/*
-			 * Eat the ":=". We already peeked, so the error should never
-			 * happen.
+			 * Eat the ":=" and the "=>". We already peeked, so the error should
+			 * never happen.
 			 */
 			tok2 = yylex(yylvalp, yyllocp, yyscanner);
-			if (tok2 != COLON_EQUALS)
+			if (tok2 != COLON_EQUALS && tok2 != EQUALS_GREATER)
 				yyerror(yyllocp, NULL, yyscanner, "syntax error");
 
 			any_named = true;
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index 0a6945581bd..31aa806e491 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -2419,7 +2419,8 @@ declare
   p2 int4 := 1006;
   n int4;
 begin
-  open c1 (p1 := p1, p2 := p2, debug := 2);
+  -- use both supported syntaxes for named arguments
+  open c1 (p1 := p1, p2 => p2, debug => 2);
   fetch c1 into n;
   return n;
 end $$ language plpgsql;
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 18c91572ae1..aaae1e44c6f 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -2072,7 +2072,8 @@ declare
   p2 int4 := 1006;
   n int4;
 begin
-  open c1 (p1 := p1, p2 := p2, debug := 2);
+  -- use both supported syntaxes for named arguments
+  open c1 (p1 := p1, p2 => p2, debug => 2);
   fetch c1 into n;
   return n;
 end $$ language plpgsql;
-- 
2.48.1