octave-qscintilla.cc

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/*

Copyright (C) 2013-2018 Torsten

This file is part of Octave.

Octave is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Octave is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<https://www.gnu.org/licenses/>.

*/

// Author: Torsten <ttl@justmail.de>

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#if defined (HAVE_QSCINTILLA)

#include <Qsci/qscilexer.h>

#if defined (HAVE_QSCI_QSCILEXEROCTAVE_H)
#  define HAVE_LEXER_OCTAVE 1
#  include <Qsci/qscilexeroctave.h>
#elif defined (HAVE_QSCI_QSCILEXERMATLAB_H)
#  define HAVE_LEXER_MATLAB 1
#  include <Qsci/qscilexermatlab.h>
#endif
#include <Qsci/qscilexercpp.h>
#include <Qsci/qscilexerbash.h>
#include <Qsci/qscilexerperl.h>
#include <Qsci/qscilexerbatch.h>
#include <Qsci/qscilexerdiff.h>

#include <Qsci/qscicommandset.h>

#include <QKeySequence>
#include <QShortcut>
#include <QToolTip>
#include <QVBoxLayout>

#include <QMimeData>

// FIXME: hardwired marker numbers?
#include "marker.h"

#include "octave-qscintilla.h"
#include "file-editor-tab.h"
#include "shortcut-manager.h"
#include "resource-manager.h"
#include "octave-settings.h"

// Return true if CANDIDATE is a "closing" that matches OPENING,
// such as "end" or "endif" for "if", or "catch" for "try".
// Used for testing the last word of an "if" etc. line,
// or the first word of the following line.

static bool
is_end (const QString& candidate, const QString& opening)
{
  bool retval = false;

  if (opening == "do")          // The only one that can't be ended by "end"
    {
      if (candidate == "until")
        retval = true;
    }
  else
    {
      if (candidate == "end")
        retval =  true;
      else
        {
          if (opening == "try")
            {
              if (candidate == "catch" || candidate == "end_try_catch")
                retval = true;
            }
          else if (opening == "unwind_protect")
            {
              if (candidate == "unwind_protect_cleanup"
                  || candidate == "end_unwind_protect")
                retval = true;
            }
          else if (candidate == "end" + opening)
            retval = true;
          else if (opening == "if" && candidate == "else")
            retval = true;
        }
    }

  return retval;
}

namespace octave
{
  octave_qscintilla::octave_qscintilla (QWidget *p)
    : QsciScintilla (p), m_word_at_cursor (), m_selection (),
      m_selection_replacement (), m_selection_line (-1),
      m_selection_col (-1), m_indicator_id (1)
  {
    connect (this, SIGNAL (textChanged (void)),
             this, SLOT (text_changed (void)));

    connect (this, SIGNAL (cursorPositionChanged (int, int)),
             this, SLOT (cursor_position_changed (int, int)));

    // clear scintilla edit shortcuts that are handled by the editor
    QsciCommandSet *cmd_set = standardCommands ();

    // Disable buffered drawing on all systems
    SendScintilla (SCI_SETBUFFEREDDRAW, false);

#if defined (HAVE_QSCI_VERSION_2_6_0)
    // find () was added in QScintilla 2.6
    cmd_set->find (QsciCommand::SelectionCopy)->setKey (0);
    cmd_set->find (QsciCommand::SelectionCut)->setKey (0);
    cmd_set->find (QsciCommand::Paste)->setKey (0);
    cmd_set->find (QsciCommand::SelectAll)->setKey (0);
    cmd_set->find (QsciCommand::SelectionDuplicate)->setKey (0);
    cmd_set->find (QsciCommand::LineTranspose)->setKey (0);
    cmd_set->find (QsciCommand::Undo)->setKey (0);
    cmd_set->find (QsciCommand::Redo)->setKey (0);
    cmd_set->find (QsciCommand::SelectionUpperCase)->setKey (0);
    cmd_set->find (QsciCommand::SelectionLowerCase)->setKey (0);
    cmd_set->find (QsciCommand::ZoomIn)->setKey (0);
    cmd_set->find (QsciCommand::ZoomOut)->setKey (0);
    cmd_set->find (QsciCommand::DeleteWordLeft)->setKey (0);
    cmd_set->find (QsciCommand::DeleteWordRight)->setKey (0);
    cmd_set->find (QsciCommand::DeleteLineLeft)->setKey (0);
    cmd_set->find (QsciCommand::DeleteLineRight)->setKey (0);
    cmd_set->find (QsciCommand::LineDelete)->setKey (0);
    cmd_set->find (QsciCommand::LineCut)->setKey (0);
    cmd_set->find (QsciCommand::LineCopy)->setKey (0);
#else
    // find commands via its default key (tricky way without find ())
    QList< QsciCommand * > cmd_list = cmd_set->commands ();
    for (int i = 0; i < cmd_list.length (); i++)
      {
        int cmd_key = cmd_list.at (i)->key ();
        switch (cmd_key)
          {
          case Qt::Key_C | Qt::CTRL :               // SelectionCopy
          case Qt::Key_X | Qt::CTRL :               // SelectionCut
          case Qt::Key_V | Qt::CTRL :               // Paste
          case Qt::Key_A | Qt::CTRL :               // SelectAll
          case Qt::Key_D | Qt::CTRL :               // SelectionDuplicate
          case Qt::Key_T | Qt::CTRL :               // LineTranspose
          case Qt::Key_Z | Qt::CTRL :               // Undo
          case Qt::Key_Y | Qt::CTRL :               // Redo
          case Qt::Key_Z | Qt::CTRL | Qt::SHIFT :   // Redo
          case Qt::Key_U | Qt::CTRL :               // SelectionLowerCase
          case Qt::Key_U | Qt::CTRL | Qt::SHIFT :   // SelectionUpperCase
          case Qt::Key_Plus | Qt::CTRL :            // ZoomIn
          case Qt::Key_Minus | Qt::CTRL :           // ZoomOut
          case Qt::Key_Backspace | Qt::CTRL | Qt::SHIFT :   // DeleteLineLeft
          case Qt::Key_Delete | Qt::CTRL | Qt::SHIFT :      // DeleteLineRight
          case Qt::Key_K | Qt::META :                       // DeleteLineRight
          case Qt::Key_Backspace | Qt::CTRL :       // DeleteWordLeft
          case Qt::Key_Delete | Qt::CTRL :          // DeleteWordRight
          case Qt::Key_L | Qt::CTRL | Qt::SHIFT :   // LineDelete
          case Qt::Key_L | Qt::CTRL :               // LineCut
          case Qt::Key_T | Qt::CTRL | Qt::SHIFT :   // LineCopy
            cmd_list.at (i)->setKey (0);
          }
      }
#endif

#if defined (Q_OS_MAC)
    // Octave interprets Cmd key as Meta whereas Qscintilla interprets it
    // as Ctrl. We thus invert Meta/Ctrl in Qscintilla's shortcuts list.
    QList< QsciCommand * > cmd_list_mac = cmd_set->commands ();
    for (int i = 0; i < cmd_list_mac.length (); i++)
      {
        // Primary key
        int key = cmd_list_mac.at (i)->key ();

        if (static_cast<int> (key | Qt::META) == key &&
            static_cast<int> (key | Qt::CTRL) != key)
          key = (key ^ Qt::META) | Qt::CTRL;
        else if (static_cast<int> (key | Qt::CTRL) == key)
          key = (key ^ Qt::CTRL) | Qt::META;

        cmd_list_mac.at (i)->setKey (key);

        // Alternate key
        key = cmd_list_mac.at (i)->alternateKey ();

        if (static_cast<int> (key | Qt::META) == key &&
            static_cast<int> (key | Qt::CTRL) != key)
          key = (key ^ Qt::META) | Qt::CTRL;
        else if (static_cast<int> (key | Qt::CTRL) == key)
          key = (key ^ Qt::CTRL) | Qt::META;

        cmd_list_mac.at (i)->setAlternateKey (key);
      }
#endif

    // selection markers

    m_indicator_id = indicatorDefine (QsciScintilla::StraightBoxIndicator);
    if (m_indicator_id == -1)
      m_indicator_id = 1;

    setIndicatorDrawUnder (true, m_indicator_id);

    markerDefine (QsciScintilla::Minus, marker::selection);

    // init state of undo/redo action for this tab
    emit status_update (isUndoAvailable (), isRedoAvailable ());
  }

  void octave_qscintilla::set_selection_marker_color (const QColor& c)
  {
    QColor ic = c;
    ic.setAlphaF (0.25);
    setIndicatorForegroundColor (ic, m_indicator_id);
    setIndicatorOutlineColor (ic, m_indicator_id);

    setMarkerForegroundColor (c, marker::selection);
    setMarkerBackgroundColor (c, marker::selection);
  }

  // context menu requested
  void octave_qscintilla::contextMenuEvent (QContextMenuEvent *e)
  {
#if defined (HAVE_QSCI_VERSION_2_6_0)
    QPoint global_pos, local_pos;                         // the menu's position
    QMenu *context_menu = createStandardContextMenu ();  // standard menu

    bool in_left_margin = false;

    // determine position depending on mouse or keyboard event
    if (e->reason () == QContextMenuEvent::Mouse)
      {
        // context menu by mouse
        global_pos = e->globalPos ();            // global mouse position
        local_pos  = e->pos ();                  // local mouse position
        if (e->x () < marginWidth (1) + marginWidth (2))
          in_left_margin = true;
      }
    else
      {
        // context menu by keyboard or other: get point of text cursor
        get_global_textcursor_pos (&global_pos, &local_pos);
        QRect editor_rect = geometry ();      // editor rect mapped to global
        editor_rect.moveTopLeft
          (parentWidget ()->mapToGlobal (editor_rect.topLeft ()));
        if (! editor_rect.contains (global_pos))  // is cursor outside editor?
          global_pos = editor_rect.topLeft ();   // yes, take top left corner
      }

#if defined (HAVE_QSCI_VERSION_2_6_0)
    if (! in_left_margin)
#endif
      {
        // fill context menu with editor's standard actions
        emit create_context_menu_signal (context_menu);

        // additional custom entries of the context menu
        context_menu->addSeparator ();   // separator before custom entries

        // help menu: get the position of the mouse or the text cursor
        // (only for octave files)
        QString lexer_name = lexer ()->lexer ();
        if (lexer_name == "octave" || lexer_name == "matlab")
          {
            m_word_at_cursor = wordAtPoint (local_pos);
            if (! m_word_at_cursor.isEmpty ())
              {
                context_menu->addAction (tr ("Help on") + ' ' + m_word_at_cursor,
                                         this, SLOT (contextmenu_help (bool)));
                context_menu->addAction (tr ("Documentation on")
                                         + ' ' + m_word_at_cursor,
                                         this, SLOT (contextmenu_doc (bool)));
                context_menu->addAction (tr ("Edit") + ' ' + m_word_at_cursor,
                                         this, SLOT (contextmenu_edit (bool)));
              }
          }
      }
#if defined (HAVE_QSCI_VERSION_2_6_0)
    else
      {
        // remove all standard actions from scintilla
        QList<QAction *> all_actions = context_menu->actions ();
        QAction *a;

        foreach (a, all_actions)
          context_menu->removeAction (a);

        a = context_menu->addAction (tr ("dbstop if ..."), this,
                                     SLOT (contextmenu_break_condition (bool)));
        a->setData (local_pos);
      }
#endif

    // finaly show the menu
    context_menu->exec (global_pos);
#endif
  }

  // common function with flag for documentation
  void octave_qscintilla::contextmenu_help_doc (bool documentation)
  {
    if (documentation)
      emit show_doc_signal (m_word_at_cursor);
    else
      emit execute_command_in_terminal_signal ("help " + m_word_at_cursor);
  }

  // call edit the function related to the current word
  void octave_qscintilla::context_edit (void)
  {
    if (get_actual_word ())
      contextmenu_edit (true);
  }

  // call edit the function related to the current word
  void octave_qscintilla::context_run (void)
  {
    if (hasSelectedText ())
      contextmenu_run (true);
  }

  void octave_qscintilla::get_global_textcursor_pos (QPoint *global_pos,
                                                     QPoint *local_pos)
  {
    long position = SendScintilla (SCI_GETCURRENTPOS);
    long point_x  = SendScintilla (SCI_POINTXFROMPOSITION,0,position);
    long point_y  = SendScintilla (SCI_POINTYFROMPOSITION,0,position);
    *local_pos = QPoint (point_x,point_y);  // local cursor position
    *global_pos = mapToGlobal (*local_pos); // global position of cursor
  }

  // determine the actual word and whether we are in an octave or matlab script
  bool octave_qscintilla::get_actual_word (void)
  {
    QPoint global_pos, local_pos;
    get_global_textcursor_pos (&global_pos, &local_pos);
    m_word_at_cursor = wordAtPoint (local_pos);
    QString lexer_name = lexer ()->lexer ();
    return ((lexer_name == "octave" || lexer_name == "matlab")
            && ! m_word_at_cursor.isEmpty ());
  }

  // helper function for clearing all indicators of a specific style
  void octave_qscintilla::clear_selection_markers (void)
  {
    int end_pos = text ().length ();
    int end_line, end_col;
    lineIndexFromPosition (end_pos, &end_line, &end_col);
    clearIndicatorRange (0, 0, end_line, end_col, m_indicator_id);

    markerDeleteAll (marker::selection);
  }

  // Function returning the true cursor position where the tab length
  // is taken into account.
  void octave_qscintilla::get_current_position (int *pos, int *line, int *col)
  {
    *pos = SendScintilla (QsciScintillaBase::SCI_GETCURRENTPOS);
    *line = SendScintilla (QsciScintillaBase::SCI_LINEFROMPOSITION, *pos);
    *col = SendScintilla (QsciScintillaBase::SCI_GETCOLUMN, *pos);
  }

  // Function returning the comment string of the current lexer
  QStringList octave_qscintilla::comment_string (bool comment)
  {
    int lexer = SendScintilla (SCI_GETLEXER);

    switch (lexer)
      {
#if defined (HAVE_LEXER_OCTAVE) || defined (HAVE_LEXER_MATLAB)
#if defined (HAVE_LEXER_OCTAVE)
      case SCLEX_OCTAVE:
#else
      case SCLEX_MATLAB:
#endif
        {
          QSettings *settings = resource_manager::get_settings ();
          int comment_string;

          if (comment)
            {
              // The commenting string is requested
              if (settings->contains (oct_comment_str))
                // new version (radio buttons)
                comment_string = settings->value (oct_comment_str,
                                                  oct_comment_str_d).toInt ();
              else
                // old version (combo box)
                comment_string = settings->value (oct_comment_str_old,
                                                  oct_comment_str_d).toInt ();

              return (QStringList (oct_comment_strings.at (comment_string)));
            }
          else
            {
              QStringList c_str;

              // The possible uncommenting string(s) are requested
              comment_string = settings->value (oct_uncomment_str,
                                                oct_uncomment_str_d).toInt ();

              for (int i = 0; i < oct_comment_strings_count; i++)
                {
                  if (1 << i & comment_string)
                    c_str.append (oct_comment_strings.at (i));
                }

              return c_str;
            }

        }
#endif

      case SCLEX_PERL:
      case SCLEX_BASH:
      case SCLEX_DIFF:
        return QStringList ("#");

      case SCLEX_CPP:
        return QStringList ("//");

      case SCLEX_BATCH:
        return QStringList ("REM ");
      }

    return QStringList ("%");  // should never happen
  }


  // provide the style at a specific position
  int octave_qscintilla::get_style (int pos)
  {
    int position;
    if (pos < 0)
      // The positition has to be reduced by 2 for getting the real style (?)
      position = SendScintilla (QsciScintillaBase::SCI_GETCURRENTPOS) - 2;
    else
      position = pos;

    return SendScintilla (QsciScintillaBase::SCI_GETSTYLEAT, position);
  }

  // Is a specific cursor position in a line or block comment?
  int octave_qscintilla::is_style_comment (int pos)
  {
    int lexer = SendScintilla (QsciScintillaBase::SCI_GETLEXER);
    int style = get_style (pos);

    switch (lexer)
      {
      case SCLEX_CPP:
        return (ST_LINE_COMMENT * (
                                   style == QsciLexerCPP::CommentLine
                                   || style == QsciLexerCPP::CommentLineDoc)
                + ST_BLOCK_COMMENT * (
                                      style == QsciLexerCPP::Comment
                                      || style == QsciLexerCPP::CommentDoc
                                      || style == QsciLexerCPP::CommentDocKeyword
                                      || style == QsciLexerCPP::CommentDocKeywordError)
                );

#if defined (HAVE_LEXER_MATLAB)
      case SCLEX_MATLAB:
        return (ST_LINE_COMMENT * (style == QsciLexerMatlab::Comment));
#endif
#if  defined (HAVE_LEXER_OCTAVE)
      case SCLEX_OCTAVE:
        return (ST_LINE_COMMENT * (style == QsciLexerOctave::Comment));
#endif

      case SCLEX_PERL:
        return (ST_LINE_COMMENT * (style == QsciLexerPerl::Comment));

      case SCLEX_BATCH:
        return (ST_LINE_COMMENT * (style == QsciLexerBatch::Comment));

      case SCLEX_DIFF:
        return (ST_LINE_COMMENT * (style == QsciLexerDiff::Comment));

      case SCLEX_BASH:
        return (ST_LINE_COMMENT * (style == QsciLexerBash::Comment));

      }

    return ST_NONE;
  }

  // Do smart indendation after if, for, ...
  void octave_qscintilla::smart_indent (bool do_smart_indent,
                                        int do_auto_close, int line)
  {
    QString prevline = text (line);

    QRegExp bkey = QRegExp ("^[\t ]*(if|for|while|switch|case|otherwise"
                            "|do|function|properties|events|classdef"
                            "|unwind_protect|unwind_protect_cleanup|try"
                            "|parfor|methods)"
                            "[\r]?[\n\t #%]");
    // last word except for comments, assuming no ' or " in comment.
    // rx_end = QRegExp ("(\\w+)[ \t;\r\n]*([%#][^\"']*)?$");

    // last word except for comments,
    // allowing % and # in single or double quoted strings
    // FIXME This will get confused by transpose.
    QRegExp ekey = QRegExp ("(?:(?:['\"][^'\"]*['\"])?[^%#]*)*"
                            "(\\w+)[ \t;\r\n]*([%#].*)?$");

    int bpos = bkey.indexIn (prevline, 0);
    int epos;

    if (bpos > -1)
      {
        // Found keyword after that indentation should be added

        // Check for existing end statement in the same line
        epos = ekey.indexIn (prevline, bpos);
        QString first_word = bkey.cap(1);
        bool inline_end = (epos > -1) && is_end (ekey.cap(1), first_word);

        if (do_smart_indent && ! inline_end)
          {
            // Do smart indent in the current line (line+1)
            indent (line+1);
            setCursorPosition (line+1, indentation (line) + indentationWidth ());
          }

        if (do_auto_close
            && ! inline_end
            && ! first_word.contains (
                                      QRegExp ("(case|otherwise|unwind_protect_cleanup)")))
          {
            // Do auto close
            auto_close (do_auto_close, line, prevline, first_word);
          }

        return;
      }

    QRegExp mkey = QRegExp ("^[\t ]*(else|elseif|catch)[\r]?[\t #%\n]");
    if (prevline.contains (mkey))
      {
        int prev_ind = indentation (line-1);
        int act_ind = indentation (line);

        if (prev_ind == act_ind)
          unindent (line);
        else if (prev_ind > act_ind)
          {
            setIndentation (line+1, prev_ind);
            setCursorPosition (line+1, prev_ind);
          }
        return;
      }

    ekey = QRegExp ("^[\t ]*(end|endif|endfor|endwhile|until|endfunction"
                    "|end_try_catch|end_unwind_protext)[\r]?[\t #%\n(;]");
    if (prevline.contains (ekey))
      {
        if (indentation (line-1) <= indentation (line))
          {
            unindent (line+1);
            unindent (line);
            setCursorPosition (line+1,
                               indentation (line));
          }
        return;
      }
  }

  // Do smart indendation of current selection or line.
  void octave_qscintilla::smart_indent_line_or_selected_text (int lineFrom,
                                                              int lineTo)
  {
    QRegExp blank_line_regexp = QRegExp ("^[\t ]*$");

    QRegExp begin_block_regexp
      = QRegExp ("^([\t ]*)(if|elseif|else"
                 "|for|while|do|parfor"
                 "|switch|case|otherwise"
                 "|function"
                 "|classdef|properties|events|enumeration|methods"
                 "|unwind_protect|unwind_protect_cleanup|try|catch)"
                 "[\r\n\t #%]");

    QRegExp end_block_regexp
      = QRegExp ("^([\t ]*)(end"
                 "|end(for|function|if|parfor|switch|while"
                 "|classdef|enumeration|events|methods|properties)"
                 "|end_(try_catch|unwind_protect)"
                 "|until)"
                 "[\r\n\t #%]");

    int indent_column = -1;
    int indent_increment = indentationWidth ();

    for (int line = lineFrom-1; line >= 0; line--)
      {
        QString line_text = text (line);

        if (blank_line_regexp.indexIn (line_text) < 0)
          {
            // Found first non-blank line above beginning of region or
            // current line.  Base indentation from this line, increasing
            // indentation by indentationWidth if it looks like the
            // beginning of a code block.

            indent_column = indentation (line);

            if (begin_block_regexp.indexIn (line_text) > -1)
              indent_column += indent_increment;

            break;
          }
      }

    if (indent_column < 0)
      indent_column = indentation (lineFrom);

    for (int line = lineFrom; line <= lineTo; line++)
      {
        QString line_text = text (line);

        if (end_block_regexp.indexIn (line_text) > -1)
          indent_column -= indent_increment;

        setIndentation (line, indent_column);

        if (begin_block_regexp.indexIn (line_text) > -1)
          indent_column += indent_increment;
      }
  }

  void octave_qscintilla::set_word_selection (const QString& word)
  {
    m_selection = word;

    if (word.isEmpty ())
      {
        m_selection_line = -1;
        m_selection_col = -1;

        m_selection_replacement = "";

        clear_selection_markers ();

        QToolTip::hideText ();
      }
    else
      {
        int pos;
        get_current_position (&pos, &m_selection_line, &m_selection_col);
      }
  }

  void octave_qscintilla::show_selection_markers (int line, int col, int len)
  {
    fillIndicatorRange (line, col - len, line, col, m_indicator_id);

    markerAdd (line, marker::selection);
  }

  void octave_qscintilla::contextmenu_help (bool)
  {
    contextmenu_help_doc (false);
  }

  void octave_qscintilla::contextmenu_doc (bool)
  {
    contextmenu_help_doc (true);
  }

  void octave_qscintilla::context_help_doc (bool documentation)
  {
    if (get_actual_word ())
      contextmenu_help_doc (documentation);
  }

  void octave_qscintilla::contextmenu_edit (bool)
  {
    emit context_menu_edit_signal (m_word_at_cursor);
  }

  void octave_qscintilla::contextmenu_run (bool)
  {
    QStringList commands = selectedText ().split (QRegExp ("[\r\n]"),
                                                  QString::SkipEmptyParts);
    for (int i = 0; i < commands.size (); i++)
      emit execute_command_in_terminal_signal (commands.at (i));
  }

  // wrappers for dbstop related context menu items

  // FIXME: Why can't the data be sent as the argument to the function???
  void octave_qscintilla::contextmenu_break_condition (bool)
  {
#if defined (HAVE_QSCI_VERSION_2_6_0)
    QAction *action = qobject_cast<QAction *>(sender ());
    QPoint local_pos = action->data ().value<QPoint> ();

    // pick point just right of margins, so lineAt doesn't give -1
    int margins = marginWidth (1) + marginWidth (2) + marginWidth (3);
    local_pos = QPoint (margins + 1, local_pos.y ());

    emit context_menu_break_condition_signal (lineAt (local_pos));
#endif
  }

  void octave_qscintilla::contextmenu_break_once (const QPoint& local_pos)
  {
#if defined (HAVE_QSCI_VERSION_2_6_0)
    emit context_menu_break_once (lineAt (local_pos));
#endif
  }

  void octave_qscintilla::text_changed (void)
  {
    emit status_update (isUndoAvailable (), isRedoAvailable ());
  }

  void octave_qscintilla::cursor_position_changed (int line, int col)
  {
    // Clear the selection if we move away from it.  We have to check the
    // position, because we allow entering text at the point of the
    // selection to trigger a search and replace that does not clear the
    // selection until it is complete.

    if (! m_selection.isEmpty ()
        && (line != m_selection_line || col != m_selection_col))
      set_word_selection ();
  }

  // when edit area gets focus update information on undo/redo actions
  void octave_qscintilla::focusInEvent (QFocusEvent *focusEvent)
  {
    emit status_update (isUndoAvailable (), isRedoAvailable ());

    QsciScintilla::focusInEvent (focusEvent);
  }

  void octave_qscintilla::show_replace_action_tooltip (void)
  {
    int pos;
    get_current_position (&pos, &m_selection_line, &m_selection_col);

    // Offer to replace other instances.

    QKeySequence keyseq = Qt::SHIFT + Qt::Key_Return;

    QString msg = (tr ("Press '%1' to replace all occurrences of '%2' with '%3'.")
                   . arg (keyseq.toString ())
                   . arg (m_selection)
                   . arg (m_selection_replacement));

    QPoint global_pos;
    QPoint local_pos;

    get_global_textcursor_pos (&global_pos, &local_pos);

    QFontMetrics ttfm (QToolTip::font ());

    // Try to avoid overlapping with the text completion dialog
    // and the text that is currently being edited.

    global_pos += QPoint (2*ttfm.maxWidth (), -3*ttfm.height ());

    QToolTip::showText (global_pos, msg);
  }

  void octave_qscintilla::keyPressEvent (QKeyEvent *key_event)
  {
    if (m_selection.isEmpty ())
      QsciScintilla::keyPressEvent (key_event);
    else
      {
        int key = key_event->key ();
        Qt::KeyboardModifiers modifiers = key_event->modifiers ();

        if (key == Qt::Key_Return && modifiers == Qt::ShiftModifier)
          {
            // get the resulting cursor position
            // (required if click was beyond a line ending)
            int pos, line, col;
            get_current_position (&pos, &line, &col);

            // remember first visible line for restoring the view afterwards
            int first_line = firstVisibleLine ();

            // search for first occurrence of the detected word
            bool find_result_available
              = findFirst (m_selection,
                           false,   // no regexp
                           true,    // case sensitive
                           true,    // whole words only
                           false,   // do not wrap
                           true,    // forward
                           0, 0,    // from the beginning
                           false
#if defined (HAVE_QSCI_VERSION_2_6_0)
                           , true
#endif
                          );

            while (find_result_available)
              {
                replace (m_selection_replacement);

                // FIXME: is this the right thing to do?  findNext doesn't
                // work properly if the length of the replacement text is
                // different from the original.

                int new_line, new_col;
                get_current_position (&pos, &new_line, &new_col);

                find_result_available
                  = findFirst (m_selection,
                               false,   // no regexp
                               true,    // case sensitive
                               true,    // whole words only
                               false,   // do not wrap
                               true,    // forward
                               new_line, new_col,    // from new pos
                               false
#if defined (HAVE_QSCI_VERSION_2_6_0)
                               , true
#endif
                              );
              }

            // restore the visible area of the file, the cursor position,
            // and the selection
            setFirstVisibleLine (first_line);
            setCursorPosition (line, col);

            // Clear the selection.
            set_word_selection ();
          }
        else
          {
            // The idea here is to allow backspace to remove the last
            // character of the replacement text to allow minimal editing
            // and to also end the selection replacement action if text is
            // not valid as a word constituent (control characters,
            // etc.).  Is there a better way than having special cases for
            // DEL and ESC here?

            QString text = key_event->text ();

            bool cancel_replacement = false;

            if (key == Qt::Key_Backspace)
              {
                if (m_selection_replacement.isEmpty ())
                  cancel_replacement = true;
                else
                  m_selection_replacement.chop (1);
              }
            else if (key == Qt::Key_Delete || key == Qt::Key_Escape)
              cancel_replacement = true;
            else if (! text.isEmpty ())
              m_selection_replacement += text;
            else if (modifiers != Qt::ShiftModifier)
              cancel_replacement = true;

            // Perform default action.

            QsciScintilla::keyPressEvent (key_event);

            if (cancel_replacement)
              set_word_selection ();

            if (! m_selection_replacement.isEmpty ())
              show_replace_action_tooltip ();
          }
      }
  }

  void octave_qscintilla::auto_close (int auto_endif, int linenr,
                                      const QString& line, QString& first_word)
  {
    // Insert and "end" for an "if" etc., if needed.
    // (Use of "while" allows "return" to skip the rest.
    // It may be clearer to use "if" and "goto",
    // but that violates the coding standards.)

    bool autofill_simple_end = (auto_endif == 2);

    size_t start = line.toStdString ().find_first_not_of (" \t");

    // Check if following line has the same or less indentation
    // Check if the following line does not start with
    //       end* (until) (catch)
    if (linenr < lines () - 1)
      {
        int offset = 1;
        size_t next_start;
        QString next_line;
        do                            // find next non-blank line
          {
            next_line = text (linenr + offset++);
            next_start = next_line.toStdString ().find_first_not_of (" \t\n");
          }
        while (linenr + offset < lines ()
               && next_start == std::string::npos);
        if (next_start == std::string::npos)
          next_start = 0;
        if (next_start > start)       // more indented => don't add "end"
          return;
        if (next_start == start)      // same => check if already is "end"
          {
            QRegExp rx_start = QRegExp (R"((\w+))");
            int tmp = rx_start.indexIn (next_line, start);
            if (tmp != -1 && is_end (rx_start.cap(1), first_word))
              return;
          }
      }

    // If all of the above, insert a new line, with matching indent
    // and either 'end' or 'end...', depending on a flag.

    // If we insert directly after the last line, the "end" is autoindented,
    // so add a dummy line.
    if (linenr + 2 == lines ())
      insertAt (QString ("\n"), linenr + 2, 0);

    // For try/catch/end, fill "end" first, so "catch" is top of undo stack
    if (first_word == "try")
      insertAt (QString (start, ' ')
                + (autofill_simple_end ? "end\n" : "end_try_catch\n"),
                linenr + 2, 0);
    else if (first_word == "unwind_protect")
      insertAt (QString (start, ' ')
                + (autofill_simple_end ? "end\n" : "end_unwind_protect\n"),
                linenr + 2, 0);

    QString next_line;
    if (first_word == "do")
      next_line = "until\n";
    else if (first_word == "try")
      next_line = "catch\n";
    else if (first_word == "unwind_protect")
      next_line = "unwind_protect_cleanup\n";
    else if (autofill_simple_end)
      next_line = "end\n";
    else
      {
        if (first_word == "unwind_protect")
          first_word = '_' + first_word;
        next_line = "end" + first_word + "\n";
      }

    insertAt (QString (start, ' ') + next_line, linenr + 2, 0);
  }

  void octave_qscintilla::dragEnterEvent (QDragEnterEvent *e)
  {
    // if is not dragging a url, pass to qscintilla to handle,
    // otherwise ignore it so that it will be handled by
    // the parent
    if (!e->mimeData ()->hasUrls ())
      {
        QsciScintilla::dragEnterEvent (e);
      }
    else
      {
        e->ignore();
      }
  }
}

#endif