Refactor parsing rules for option lists of EXPLAIN, VACUUM and ANALYZE

Those three commands have been using the same grammar rules to handle a
a list of parenthesized options.  This refactors the code so as they use
the same parsing rules, shaving some code.  A future commit will make
use of those option parsing rules for more utility commands, like
REINDEX and CLUSTER.

Author: Alexey Kondratov, Justin Pryzby
Discussion: https://postgr.es/m/8a8f5f73-00d3-55f8-7583-1375ca8f6a91@postgrespro.ru

src/backend/parser/gram.y

@@ -315,10 +315,10 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 				create_extension_opt_item alter_extension_opt_item
 
 %type <ival>	opt_lock lock_type cast_context
-%type <str>		vac_analyze_option_name
-%type <defelt>	vac_analyze_option_elem
-%type <list>	vac_analyze_option_list
-%type <node>	vac_analyze_option_arg
+%type <str>		utility_option_name
+%type <defelt>	utility_option_elem
+%type <list>	utility_option_list
+%type <node>	utility_option_arg
 %type <defelt>	drop_option
 %type <boolean>	opt_or_replace opt_no
 				opt_grant_grant_option opt_grant_admin_option
@@ -513,10 +513,6 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <node>	generic_option_arg
 %type <defelt>	generic_option_elem alter_generic_option_elem
 %type <list>	generic_option_list alter_generic_option_list
-%type <str>		explain_option_name
-%type <node>	explain_option_arg
-%type <defelt>	explain_option_elem
-%type <list>	explain_option_list
 
 %type <ival>	reindex_target_type reindex_target_multitable
 %type <ival>	reindex_option_list reindex_option_elem
@@ -10483,7 +10479,7 @@ VacuumStmt: VACUUM opt_full opt_freeze opt_verbose opt_analyze opt_vacuum_relati
 					n->is_vacuumcmd = true;
 					$$ = (Node *)n;
 				}
-			| VACUUM '(' vac_analyze_option_list ')' opt_vacuum_relation_list
+			| VACUUM '(' utility_option_list ')' opt_vacuum_relation_list
 				{
 					VacuumStmt *n = makeNode(VacuumStmt);
 					n->options = $3;
@@ -10504,7 +10500,7 @@ AnalyzeStmt: analyze_keyword opt_verbose opt_vacuum_relation_list
 					n->is_vacuumcmd = false;
 					$$ = (Node *)n;
 				}
-			| analyze_keyword '(' vac_analyze_option_list ')' opt_vacuum_relation_list
+			| analyze_keyword '(' utility_option_list ')' opt_vacuum_relation_list
 				{
 					VacuumStmt *n = makeNode(VacuumStmt);
 					n->options = $3;
@@ -10514,12 +10510,12 @@ AnalyzeStmt: analyze_keyword opt_verbose opt_vacuum_relation_list
 				}
 		;
 
-vac_analyze_option_list:
-			vac_analyze_option_elem
+utility_option_list:
+			utility_option_elem
 				{
 					$$ = list_make1($1);
 				}
-			| vac_analyze_option_list ',' vac_analyze_option_elem
+			| utility_option_list ',' utility_option_elem
 				{
 					$$ = lappend($1, $3);
 				}
@@ -10530,19 +10526,19 @@ analyze_keyword:
 			| ANALYSE /* British */
 		;
 
-vac_analyze_option_elem:
-			vac_analyze_option_name vac_analyze_option_arg
+utility_option_elem:
+			utility_option_name utility_option_arg
 				{
 					$$ = makeDefElem($1, $2, @1);
 				}
 		;
 
-vac_analyze_option_name:
+utility_option_name:
 			NonReservedWord							{ $$ = $1; }
 			| analyze_keyword						{ $$ = "analyze"; }
 		;
 
-vac_analyze_option_arg:
+utility_option_arg:
 			opt_boolean_or_string					{ $$ = (Node *) makeString($1); }
 			| NumericOnly							{ $$ = (Node *) $1; }
 			| /* EMPTY */							{ $$ = NULL; }
@@ -10624,7 +10620,7 @@ ExplainStmt:
 					n->options = list_make1(makeDefElem("verbose", NULL, @2));
 					$$ = (Node *) n;
 				}
-		| EXPLAIN '(' explain_option_list ')' ExplainableStmt
+		| EXPLAIN '(' utility_option_list ')' ExplainableStmt
 				{
 					ExplainStmt *n = makeNode(ExplainStmt);
 					n->query = $5;
@@ -10645,35 +10641,6 @@ ExplainableStmt:
 			| ExecuteStmt					/* by default all are $$=$1 */
 		;
 
-explain_option_list:
-			explain_option_elem
-				{
-					$$ = list_make1($1);
-				}
-			| explain_option_list ',' explain_option_elem
-				{
-					$$ = lappend($1, $3);
-				}
-		;
-
-explain_option_elem:
-			explain_option_name explain_option_arg
-				{
-					$$ = makeDefElem($1, $2, @1);
-				}
-		;
-
-explain_option_name:
-			NonReservedWord			{ $$ = $1; }
-			| analyze_keyword		{ $$ = "analyze"; }
-		;
-
-explain_option_arg:
-			opt_boolean_or_string	{ $$ = (Node *) makeString($1); }
-			| NumericOnly			{ $$ = (Node *) $1; }
-			| /* EMPTY */			{ $$ = NULL; }
-		;
-
 /*****************************************************************************
  *
  *		QUERY: