<* PRAGMA LL *>

INTERFACE MacModel;

IMPORT TextPortClass;

TYPE T <: TextPortClass.Model;

END MacModel.

The conventions for the Mac model are taken from Apple's {\it Human Interface Guidelines} \cite[pages 106-114]{AppleUI}.

The first unmodified downclick establishes the {\it anchor point}. If the user then drags the mouse, the upclick establishes the {\it active end}; the range between the anchor point and the active end is the Primary selection, and it is highlighted. If the user releases the mouse without dragging, that establishes the {\it type-in point}, and there is no selection or highlighting.

Shift-downclick extends (or reduces) the primary selection and establishes the new active end.

Double-clicking selects a word; dragging after a double-click extends the selection in word-size increments.

The Mac model implements the following Apple guidelines:

\begin{quote}

When a Shift-arrow key combination is pressed, the active end of the selection moves and the range over which it moves becomes selected. ... Option-Shift-Left Arrow selects the whole word that contains the character to the left of the insertion point (just like double-clicking on a word).

In a text application, pressing Shift and either Left Arrow or Right Arrow selects a single character. Assuming that the Left Arrow key was used, the anchor point of the selection is on the right side of the selection, the active end on the left. Each subsequent Shift-Left Arrow adds another character to the left side of the selection. A Shift-Right Arrow at this point shrinks the selection.

Pressing Option-Shift and either Left Arrow or Right Arrow ... selects the entire word containing the character to the left of the insertion point. Assuming Left Arrow was pressed, the anchor point is at the right end of the word, the active end at the left. Each subsequent Option-Shift-Left Arrow adds another word to the left end of the selection...

When a block of text is selected, either with a pointing device or with cursor keys, pressing either Left Arrow or Right Arrow deselects the range. If Left Arrow is pressed, the insertion point goes to the beginning of what had been the selection. If Right Arrow is pressed, the insertion point goes to the end of what had been the selection.

[From page 83] When the user chooses Cut, ... the place where the selection used to be becomes the new selection. ... In text, the new selection is an insertion point [and the highlighting is removed].

Paste ... inserts the contents of the Clipboard [Source] into the document, replacing the current selection [i.e., Primary selections are always replace-mode]. If there is no current selection, it's inserted at the insertion point.... After a Paste, the new selection is ... an insertion point immediately after the pasted text. [In either case, there is no highlighting.]

\end{quote}

In documentation from Apple, Mac keybindings are typically described in terms of ``command'' and ``option'' modifiers. DEC keyboards and the X server do not use those terms, but a correspondence can be established. The Mac model uses the value of environment variable MacCommandModifier\index{MacCommandModifier} to name the X-modifier that the user would like to behave as if it were the ``command'' key. The choices are:

      lock, control, mod1, mod2, mod3, mod4, and mod5
   

Similarly, the Mac model uses the environment variable MacOptionModifier\index{MacOptionModifier} to name the X-modifier that the user would like to behave as if it were the ``option'' key. The choices are the same as in the list above. The default is mod1.

The following commands are implemented in the Mac model:

\begin{center} \begin{tabbing} LongCommandKeyName \= This is just a tab-setting line. \kill command-c \> {\bf Copy} \\ command-v \> {\bf Paste} \\ command-x \> {\bf Cut} \\ command-z \> {\bf Undo} \\ command-shift-z \> {\bf Redo} \\ \end{tabbing} \end{center}

The Mac model supports the Apple standards for typing extended characters, insofar as the resulting characters are defined for ISO Latin-1. For example, option-g produces the copyright symbol, \copyright, but option-shift-7, which produces a double dagger, \ddag, on the Macintosh, produces no key in the Mac model, since the double-dagger is not in ISO Latin-1. The Mac model supports all the two-character sequences, such as option-e followed by ``a'' to produce ``a'' with an acute accent, \'{a}. The complete table appears on page~\pageref{MacExtendedCharacters}.