<* PRAGMA LL *>

INTERFACE EmacsModel;

IMPORT KeyFilter, TextPortClass;

TYPE
  T <: TextPortClass.Model;
  EscapeMetaFilter <: KeyFilter.T;

END EmacsModel.

The model supports a single {\it region}, which is delimited by the {\it mark} and the {\it point}. Control-space and control-@ set the mark; the point is the same as the current cursor position, which is changed by mouse-gestures, cursor-keys, or control-keys. When the region is established by cursor-keys or control-keys, it is not highlighted. If the region is highlighted, then any gesture that extends it will extend the highlighting as well.

A single left-click sets the point and ensures that the current selection is not in replace-mode. 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. A double left-click sets both the mark and the point.

The Cut and Copy commands make a copy of the text in the region (i.e., the Primary selection); it becomes the Source selection. Middle-click and meta-w call Copy.

Right-click extends and highlights the current 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. The Emacs model supports ``Escape + character'' as an alternate way to type ``meta-character,'' and ISO Latin-1 character composition. See Section~\ref{MetaOptionKeys} for an explanation of ``meta'' keys and composition.)

\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}