MODULE edit;

(* A small full-screen editor, Turbo-Pascal style: a window containing a
   multi-line editor with its own status row, plus a File menu
   (New / Save / Quit).

   Arrows, Home/End, PgUp/PgDn move; Ins toggles insert/overwrite; Tab
   indents; the mouse positions the cursor and the wheel scrolls.  It loads
   and saves "tvision-edit.txt". *)

FROM InOut IMPORT WriteString, WriteLn;
FROM SYSTEM IMPORT ADR, CAST;
IMPORT tv;

CONST
    mNew    = 100;
    mSave   = 101;
    mQuit   = 102;
    mModula2 = 110;
    mPascal  = 111;
    mOberon  = 112;

VAR
    ed : tv.EditorData;
    edp : tv.EditorDataPtr;
    w, edView, bar : tv.ViewPtr;
    e : tv.Event;
    quit : BOOLEAN;
    cmd : INTEGER;
    sender : tv.ViewPtr;
    status : ARRAY [0..95] OF CHAR;

PROCEDURE Sample;
BEGIN
    tv.EditorInit(edp);
    tv.EditorAddLine(edp, "MODULE hello;   (* sample for tvision-m2 *)");
    tv.EditorAddLine(edp, "");
    tv.EditorAddLine(edp, "FROM InOut IMPORT WriteString, WriteLn;");
    tv.EditorAddLine(edp, "");
    tv.EditorAddLine(edp, "BEGIN");
    tv.EditorAddLine(edp, "    WriteString('Hello, world.'); WriteLn");
    tv.EditorAddLine(edp, "END hello.");
    ed.dirty := FALSE
END Sample;

PROCEDURE Refresh;
BEGIN
    IF tv.EditorDirty(edp) THEN
        tv.SetText(bar, " Ins/arrows/Tab edit   F10: menu   * modified")
    ELSE
        tv.SetText(bar, " Ins/arrows/Tab edit   F10: menu     saved")
    END;
    tv.Finish
END Refresh;

BEGIN
    IF NOT tv.Init() THEN
        WriteString("not a tty"); WriteLn; HALT
    END;

    edp := CAST(tv.EditorDataPtr, ADR(ed));

    tv.MenuBarInit;
    tv.MenuAdd("File");
    tv.MenuItemAdd("New", mNew);
    tv.MenuItemAdd("Save", mSave);
    tv.MenuSep;
    tv.MenuItemAdd("Quit", mQuit);
    tv.MenuAdd("Syntax");
    tv.MenuItemAdd("Modula-2", mModula2);
    tv.MenuItemAdd("Pascal", mPascal);
    tv.MenuItemAdd("Oberon", mOberon);

    bar := tv.NewView(tv.VText, 0, tv.Rows() - 1, tv.Cols(), 1);
    tv.AddView(tv.Desk(), bar);

    w := tv.NewView(tv.VWindow, 1, 1, tv.Cols() - 2, tv.Rows() - 3);
    tv.SetText(w, "Editor");
    tv.AddView(tv.Desk(), w);

    IF NOT tv.EditorLoad(edp, "tvision-edit.txt") THEN Sample END;
    tv.EditorSetLanguage(edp, tv.langModula2);
    tv.EditorSetIndent(edp, 2);

    edView := tv.NewView(tv.VEditor, 2, 2, tv.Cols() - 4, tv.Rows() - 5);
    tv.EditorAttach(edView, CAST(tv.EditorDataPtr, ADR(ed)));
    tv.AddView(w, edView);
    tv.FocusView(edView);

    Refresh;
    quit := FALSE;
    WHILE NOT quit DO
        IF tv.Resized() THEN Refresh END;
        IF tv.ReadEvent(e) THEN
            IF (e.kind = tv.evKey) AND (e.key = tv.kEsc) THEN
                quit := TRUE
            ELSE
                cmd := tv.HandleEvent(e);
                sender := tv.Sender();
                IF cmd = mQuit THEN
                    quit := TRUE
                ELSIF cmd = mNew THEN
                    tv.EditorInit(edp);
                    tv.EditorSetLanguage(edp, tv.langModula2);
                    tv.EditorSetIndent(edp, 2);
                    Refresh
                ELSIF cmd = mSave THEN
                    IF tv.EditorSave(edp, "tvision-edit.txt") THEN
                        tv.Message("Save", "Saved tvision-edit.txt.")
                    ELSE
                        tv.Message("Save", "Could not save the file.")
                    END;
                    Refresh
                ELSIF cmd = mModula2 THEN
                    tv.EditorSetLanguage(edp, tv.langModula2); Refresh
                ELSIF cmd = mPascal THEN
                    tv.EditorSetLanguage(edp, tv.langPascal); Refresh
                ELSIF cmd = mOberon THEN
                    tv.EditorSetLanguage(edp, tv.langOberon); Refresh
                ELSIF cmd = tv.cmClose THEN
                    quit := TRUE
                END
            END;
            IF NOT quit THEN Refresh END
        END
    END;

    tv.Done
END edit.