Streamline QRegExp instances in libgu. * file-editor-tab.cc (do_comment_selected_text): Use non-capturing grouping. * octave-qscintilla.cc (smart_indent): Use non-capturing grouping for ekey, mkey, case_key, and stand-alone QRegExp. * octave-qscintilla.cc (smart_indent_line_or_selected_text): Use non-capturing grouping for end_word_regexp, begin_block_regexp, mid_block_regexp, end_block_regexp, case_block_regexp. * qt-interpreter-events.cc (make_filter_list): Use C++ Raw string to define QRegExp with lots of backslashes. * variable-editor.cc (variable_editor_stack::levulUp): Rewrite QRegExp to use character classes to get rid of excessive backslashes.

--- a/libgui/src/qt-interpreter-events.cc	Sat Jan 04 17:16:59 2020 -0800
+++ b/libgui/src/qt-interpreter-events.cc	Mon Jan 06 10:18:00 2020 -0800
@@ -84,10 +84,9 @@
         QString ext = QString::fromStdString (ext_name.first);
         QString name = QString::fromStdString (ext_name.second);
 
-        // Strip out extensions from name and replace ';' with spaces in
-        // list.
+        // Strip out extensions from name and replace ';' with spaces in list.
 
-        name.replace (QRegExp ("\\(.*\\)"), "");
+        name.replace (QRegExp (R"(\(.*\))"), "");
         ext.replace (";", " ");
 
         if (name.isEmpty ())