(* Copyright (C) 1992 Digital Equipment Corporation                          *)
(* All rights reserved.                                                      *)
(* See the file COPYRIGHT for a full description.                            *)
(*                                                                           *)
(* Last modified on Sat Jan  2 22:49:52 PST 1993 by meehan                   *)
<* PRAGMA LL *>

INTERFACE EmacsModel;

IMPORT TextPortClass;

TYPE T <: TextPortClass.Model;

END EmacsModel. 

(* In the Emacs model, there is only a primary selection, and it
   corresponds to "VBT.Source".

   The model supports a single {\it region}, which is delimited by the
   ``mark'' and the ``point''.  Control-space and control-@ set the
   mark; the point is the same as the current cursor position, which
   is changed both by mouse-gestures and by control-keys.  When the
   region is defined by control-keys, it is not highlighted.

   A left-downclick also sets the point.  If you then drag the mouse,
   the location of the downclick becomes the mark, and the point is
   set to the current position of the mouse.  When the region is
   defined by dragging, it is highlighted.

   The Cut and Copy commands make a copy of the text in the region; it
   becomes the source selection.

   The control- and meta-keys in the Emacs model are not
   case-sensitive; control-shift-a, for example, has the same effect
   as control-a.  ``meta'' keys are those whose "modifiers" field
   contains "VBT.Modifiers.Option", as well as those that follow the
   escape key.  For example, the two-key sequence of escape followed
   by ``b'' is ``meta-b'', just like the single, modified key that
   Trestle reports as ``option-b''.

\begin{center}
\begin{tabbing}
option-LongKeyName \= This is just a tab-setting line. \kill
 control-space \> set the mark \\
 control-a \> move to the beginning of the line \\
 control-b \> move to the previous character \\
 meta-b \> move to the previous word \\
 control-d \> delete the next character \\
 meta-d \> delete the next word \\
 control-e \> move to the end of the line \\
 control-f \> move to the next character \\
 meta-f \> move to the next word \\
 control-h \> delete the previous character, and move left \\
 meta-h \> delete to the start of the current word \\
 control-i \> invoke the "tabAction" callback \\
 control-j \> insert a newline \\
 control-k \> delete to the end of the line, and make that the source selection \\
 control-m \> invoke the "returnAction" callback \\
 control-n \> move down one line \\
 control-o \> insert a newline without moving the cursor \\
 control-p \> move up one line \\
 control-q \> insert the next character (``quoted insert'')\\
 control-r \> search backward for the current source selection \\
 control-s \> search forward for the current source selection \\
 control-t \> swap the current and previous characters \\
 control-v \> scroll up one screen \\
 meta-v \> scroll down one screen \\
 control-w \> {\bf Cut} \\
 meta-w \> {\bf Copy} \\
 control-y \> {\bf Paste} \\
 control-z \> scroll up one line \\
 meta-z \> scroll down one line \\
 control-\_ \> {\bf Undo} \\
 meta-\_ \> {\bf Redo} \\
 meta-< \> move to the beginning of the buffer \\
 meta-> \> move to the end of the buffer \\
 meta-leftArrow \> move to the previous word (like meta-b) \\
 meta-rightArrow \> move to the next word (like meta-f)

\end{tabbing}
\end{center}




   *)