# menuweb.t | documentation

    #charset "us-ascii"

    /*
     *   TADS 3 Library - Menu System, console edition
     *
     *   This implements the menusys user interface for the traditional
     *   console-mode interpreters.
     */
    #include "advlite.h"

    /* ------------------------------------------------------------------------ */
    /*
     *   Menu Item - user interface implementation for the console
     */
    modify MenuItem
        /*
         *   Call menu.display when you're ready to show the menu.  This
         *   should be called on the top-level menu; we run the entire menu
         *   display process, and return when the user exits from the menu
         *   tree.
         */
        display()
        {
            /* save the top-level key list */
            MenuItem.curKeyList = keyList;

            /* set myself as the current menu and the top-level menu */
            MenuItem.topMenu = self;
            MenuItem.curMenu = self;

            /* display the menu in the javascript client */
            showMenu(nil);

            /* process network events until the user closes the menu */
            MenuItem.isOpen = true;
            processNetRequests({: !MenuItem.isOpen });
        }

        /* current menu, and current top-level menu */
        curMenu = nil
        topMenu = nil

        /* is the menu open? */
        isOpen = nil

        /* show this menu as a submenu */
        showMenu(from)
        {
            /* get the XML representation of the menu item list */
            local xml = '<menusys><<getXML(from)>></menusys>';

            /* tell the javascript client to display the menu */
            webMainWin.sendWinEvent(xml);

            /* save this in the main window as the current menu state */
            webMainWin.menuSysState = xml;
        }

        /* navigate into a submenu */
        enterSubMenu(idx)
        {
            /* validate the index and select the new menu */
            if (idx >= 1 && idx <= contents.length())
            {
                /* get the new menu */
                local m = contents[idx];

                /* note the new menu location */
                MenuItem.curMenu = m;

                /* show the new menu */
                m.showMenu(self);
            }
        }

        /*
         *   Package my menu items as XML, to send to the javascript API.
         *   'from' is the menu we just navigated from, if any.  This is nil
         *   when we enter the top level menu, since we're not navigating from
         *   another menu; when we navigate from a parent to a child, this is
         *   the parent; when we return from a child to a parent, this is the
         *   child; and when we move directly from sibling to sibling (via a
         *   next/previous chapter command), this is the sibling.  When we
         *   display a new topic in a topic list menu, this is simply 'self'.
         */
        getXML(from)
        {
            /* set up a string buffer for the xml */
            local s = new StringBuffer();

            /* update the menu contents */
            updateContents();

            /* start with the menu title */
            s.append('<title><<title.htmlify()>></title>');

            /* note if we're the top-level menu */
            if (location == nil || MenuItem.topMenu == self)
                s.append('<isTop/>');

            /* run through the contents */
            for (local item in contents)
                s.append('<menuItem><<item.title.htmlify()>></menuItem>');

            /* if the 'from' menu is a child, initially select it */
            local idx = contents.indexOf(from);
            if (idx != nil)
                s.append('<fromChild><<idx>></fromChild>');

            /* add the keys */
            getKeysXML(s);

            /* return the string */
            return toString(s);
        }

        /* get the XML description of the top-level key list */
        getKeysXML(buf)
        {
            buf.append('<keylists>');
            for (local kl in curKeyList)
            {
                buf.append('<keylist>');
                for (local k in kl)
                {
                    if (k == ' ')
                        k = 'U+0020';
                    buf.append('<key><<k>></key>');
                }
                buf.append('</keylist>');
            }
            buf.append('</keylists>');
        }

        /*
         *   Prepare a title or content string for our XML output.  If 'val' is
         *   a string, we'll run it through the output formatter to expand any
         *   special <.xxx> sequences.  If 'val' is a property, we'll evaluate
         *   the property of self, capturing the output if it generates any or
         *   capturing the string if it returns one.  In all cases, we take the
         *   result string and convert TADS special characters to HTML, and
         *   finally html-escape the result for inclusion in XML output, and
         *   return the resulting string.
         */
        formatXML(func)
        {
            /* call the function and process it through the menu stream filters */
            local txt = menuOutputStream.captureOutput(func);

            /* convert special characters and html-escape the result */
            return txt.specialsToHtml().htmlify();
        }
    ;

    /*
     *   Menu system UI request processor.  This receives requests from the
     *   javascript client in response to user actions: selecting a menu item,
     *   navigating to the parent menu, closing the menu.
     */
    menuSysEventPage: WebResource
        vpath = '/webui/menusys'
        processRequest(req, query)
        {
            /* check the action type */
            if (query.isKeyPresent('close'))
            {
                /* close the menu */
                MenuItem.isOpen = nil;
            }
            else if (query.isKeyPresent('prev'))
            {
                /* go to the parent menu, or close the menu if at the top */
                local cur = MenuItem.curMenu;
                if (cur != nil && cur != MenuItem.topMenu && cur.location != nil)
                {
                    /* go to the parent */
                    local par = cur.location;
                    MenuItem.curMenu = par;
                    par.showMenu(cur);
                }
                else
                {
                    /* there's no parent - close the menu */
                    MenuItem.isOpen = nil;

                    /* tell the UI to close its menu dialog */
                    webMainWin.sendWinEvent('<menusys><close/></menusys>');
                    webMainWin.menuSysState = '';
                }
            }
            else if (query.isKeyPresent('select'))
            {
                /*
                 *   Select a child menu.  The 'select=n' parameter is the
                 *   index in the current menu's child list of the new item to
                 *   select.  Retrieve the index.
                 */
                MenuItem.curMenu.enterSubMenu(toInteger(query['select']));
            }
            else if (query.isKeyPresent('nextTopic'))
            {
                /* get the next topic in the current topic menu */
                sendAck(req, MenuItem.curMenu.getNextTopicXML());

                /* rebuild the menu state for the change */
                webMainWin.menuSysState =
                    '<menusys><<MenuItem.curMenu.getXML(MenuItem.curMenu)
                      >></menusys>';

                /* we've sent our reply, so we're done */
                return;
            }
            else if (query.isKeyPresent('chapter'))
            {
                /* get the next or previous chapter, as applicable */
                local dir = query['chapter'];
                local m = MenuItem.curMenu;
                local par = m.location;
                local nxt = (dir == 'next'
                             ? par.getNextMenu(m) : par.getPrevMenu(m));

                /* enter this chapter */
                if (nxt != nil)
                {
                    MenuItem.curMenu = nxt;
                    nxt.showMenu(m);
                }
            }

            /* acknowledge the request */
            sendAck(req);
        }
    ;

    /* ------------------------------------------------------------------------ */
    /*
     *   Menu topic item - console UI implementation
     */
    modify MenuTopicItem
        /* get the XML description of my menu list */
        getXML(from)
        {
            /* start with an empty result buffer */
            local s = new StringBuffer();

            /* update our contents, as needed */
            updateContents();

            /* add the title and total number of items in the menu */
            s.append('<title><<title.htmlify()>></title>'
                     + '<numItems><<menuContents.length()>></numItems>');

            /* note if we're the top-level menu */
            if (location == nil || MenuItem.topMenu == self)
                s.append('<isTop/>');

            /* add each item in our list */
            for (local i in 1..lastDisplayed)
                s.append(getTopicXML(i));

            /* add the keys */
            getKeysXML(s);

            /* return the XML string */
            return toString(s);
        }

        /* get the next topic, in XML format */
        getNextTopicXML()
        {
            /* if we're not already at the last item, advance the counter */
            if (lastDisplayed < menuContents.length())
                ++lastDisplayed;

            /* format the last item */
            return getTopicXML(lastDisplayed);
        }

        /* get the XML formatted description of the item at the given index */
        getTopicXML(i)
        {
            /* get the item */
            local item = menuContents[i];

            /* get the item's text, and format as XML */
            item = formatXML(dataType(item) == TypeObject
                             ? {: item.getItemText() } : item);

            /* format the item text */
            return '<topicItem><<item>></topicItem>';
        }
    ;

    /* ------------------------------------------------------------------------ */
    /*
     *   Long topic item
     */
    modify MenuLongTopicItem
        /* get my XML description */
        getXML(from)
        {
            /* start with an empty result buffer */
            local s = new StringBuffer();

            /* update our contents, as needed */
            updateContents();

            /* add my title (heading) */
            local t = heading != nil && heading != '' ? heading : title;
            s.append('<title><<t.htmlify()>></title>');

            /* add our contents */
            s.append('<longTopic><<formatXML({: menuContents })>></longTopic>');

            /*
             *   if this is a chapter menu, note if we have links for the next
             *   and previous chapters
             */
            if (isChapterMenu)
            {
                local m;

                if ((m = location.getNextMenu(self)) != nil)
                    s.append('<nextChapter><<m.title.htmlify()>></nextChapter>');

                if ((m = location.getPrevMenu(self)) != nil)
                    s.append('<prevChapter><<m.title.htmlify()>></prevChapter>');
            }

            /* add the keys */
            getKeysXML(s);

            /* return the XML string */
            return toString(s);
        }
    ;

Adv3Lite Library Reference Manual
Generated on 12/12/2022 from adv3Lite version 1.6