
    <<XTkHelpStringsImpl.mesa>>
        <<Copyright Ó 1992 by Xerox Corporation.  All rights reserved.>>
        <<Created by Christian Jacobi, March 9, 1992 3:33 pm PST>>
        <<Christian Jacobi, March 10, 1992 3:57 pm PST>>
        <<>>
    DIRECTORY 
        HelpStrings,
        Rope,
        XTk,
        XTkHelpStrings, 
        XTkHelpWidgets, 
        XTkLabels;

    XTkHelpStringsImpl: CEDAR MONITOR 
        IMPORTS XTk, XTkLabels
        EXPORTS XTkHelpStrings, XTkHelpWidgets =
    BEGIN 

    myKey: ATOM ~ $XTkHelpWidgetsImpl;
    clear: Rope.ROPE ~ "                                  ";

    Create: PUBLIC PROC [widgetSpec: XTk.WidgetSpec ¬ []] RETURNS [w: XTk.Widget, h: HelpStrings.Handle] = {
        w ¬ XTkLabels.CreateLabel[widgetSpec, clear];
        h ¬ MyCreateHandle[w];
        SetHandle[w, h];
        };
         
    GetHandle: PUBLIC PROC [w: XTk.Widget] RETURNS [HelpStrings.Handle ¬ NIL] = {
        WITH XTk.GetWidgetProp[w, myKey] SELECT FROM
            h: HelpStrings.Handle => RETURN [h];
            ENDCASE => {};
        w ¬ XTk.RootWidget[w];
        IF w#NIL THEN { 
            WITH XTk.GetWidgetProp[w, myKey] SELECT FROM
                h: HelpStrings.Handle => RETURN [h];
                ENDCASE => {};
            };
        };

    SetHandle: PUBLIC PROC [w: XTk.Widget, h: HelpStrings.Handle] = {
        XTk.PutWidgetProp[w, myKey, h];
        };

    myHelpClass: REF HelpStrings.ClassRec ~ NEW[HelpStrings.ClassRec ¬ [
        display: MyDisplay,
        clear: MyClear,
        makeVisible: NoVisible,
        hide: NoVisible,
        more: NIL
        ]];

    MyData: TYPE = RECORD [
        label: XTk.Widget ¬ NIL,
        string: REF ¬ NIL,
        key: REF ¬ NIL
        ];

    MyCreateHandle: PROC [w: XTk.Widget] RETURNS [h: HelpStrings.Handle ¬ NIL] = {
        md: REF MyData ~ NEW[MyData ¬ [label: w]];
        h ¬ NEW [HelpStrings.HandleRec ¬ [myHelpClass, md]] 
        };

    MyDisplay: PROC [h: HelpStrings.Handle, string: REF, key: REF ¬ NIL] = {
        WITH h.data SELECT FROM
            md: REF MyData => {
                text: Rope.ROPE ¬ NIL;
                WITH string SELECT FROM
                    r: Rope.ROPE => text ¬ r;
                    ENDCASE => RETURN;
                md.string ¬ string; md.key ¬ key;
                XTkLabels.SetText[md.label, text, immediately];
                };
            ENDCASE => {}
        };

    MyClear: PROC [h: HelpStrings.Handle, string: REF, key: REF ¬ NIL] = {
        WITH h.data SELECT FROM
            md: REF MyData => {
                IF md.string=string OR md.key=key THEN XTkLabels.SetText[md.label, clear, delayed];
                };
            ENDCASE => {}
        };

    NoVisible: PROC [h: HelpStrings.Handle, data: REF] = {};

    END.