Add display of oprcode (the underlying function's name) to psql's \do+.

The + modifier of \do didn't use to do anything, but now it adds an oprcode
column.  This is useful both as an additional form of documentation of what
the operator does, and to save a step when finding out properties of the
underlying function.

Marko Tiikkaja, reviewed by Rushabh Lathia, adjusted a bit by me

src/bin/psql/command.c

@@ -410,7 +410,7 @@ exec_command(const char *cmd,
 				success = listSchemas(pattern, show_verbose, show_system);
 				break;
 			case 'o':
-				success = describeOperators(pattern, show_system);
+				success = describeOperators(pattern, show_verbose, show_system);
 				break;
 			case 'O':
 				success = listCollations(pattern, show_verbose, show_system);

src/bin/psql/describe.c

@@ -577,9 +577,10 @@ describeTypes(const char *pattern, bool verbose, bool showSystem)
 
 
 /* \do
+ * Describe operators
  */
 bool
-describeOperators(const char *pattern, bool showSystem)
+describeOperators(const char *pattern, bool verbose, bool showSystem)
 {
 	PQExpBufferData buf;
 	PGresult   *res;
@@ -605,16 +606,23 @@ describeOperators(const char *pattern, bool showSystem)
 					  "  o.oprname AS \"%s\",\n"
 					  "  CASE WHEN o.oprkind='l' THEN NULL ELSE pg_catalog.format_type(o.oprleft, NULL) END AS \"%s\",\n"
 					  "  CASE WHEN o.oprkind='r' THEN NULL ELSE pg_catalog.format_type(o.oprright, NULL) END AS \"%s\",\n"
-				   "  pg_catalog.format_type(o.oprresult, NULL) AS \"%s\",\n"
-			 "  coalesce(pg_catalog.obj_description(o.oid, 'pg_operator'),\n"
-	"           pg_catalog.obj_description(o.oprcode, 'pg_proc')) AS \"%s\"\n"
-					  "FROM pg_catalog.pg_operator o\n"
-	  "     LEFT JOIN pg_catalog.pg_namespace n ON n.oid = o.oprnamespace\n",
+				  "  pg_catalog.format_type(o.oprresult, NULL) AS \"%s\",\n",
 					  gettext_noop("Schema"),
 					  gettext_noop("Name"),
 					  gettext_noop("Left arg type"),
 					  gettext_noop("Right arg type"),
-					  gettext_noop("Result type"),
+					  gettext_noop("Result type"));
+
+	if (verbose)
+		appendPQExpBuffer(&buf,
+						  "  o.oprcode AS \"%s\",\n",
+						  gettext_noop("Function"));
+
+	appendPQExpBuffer(&buf,
+			 "  coalesce(pg_catalog.obj_description(o.oid, 'pg_operator'),\n"
+	"           pg_catalog.obj_description(o.oprcode, 'pg_proc')) AS \"%s\"\n"
+					  "FROM pg_catalog.pg_operator o\n"
+	  "     LEFT JOIN pg_catalog.pg_namespace n ON n.oid = o.oprnamespace\n",
 					  gettext_noop("Description"));
 
 	if (!showSystem && !pattern)

src/bin/psql/describe.h

@@ -22,7 +22,7 @@ extern bool describeFunctions(const char *functypes, const char *pattern, bool v
 extern bool describeTypes(const char *pattern, bool verbose, bool showSystem);
 
 /* \do */
-extern bool describeOperators(const char *pattern, bool showSystem);
+extern bool describeOperators(const char *pattern, bool verbose, bool showSystem);
 
 /* \du, \dg */
 extern bool describeRoles(const char *pattern, bool verbose);