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              <html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Matrix/mxWeb • An Introduction</title>

    <link href="https://rawgit.com/kennytilton/matrix/master/js/matrix/css/todomvcish.css"
           rel="stylesheet">
  
    <script src="https://rawgit.com/kennytilton/matrix/master/js/matrix/public/mxweb.smp.js">
  </script>
  
</head>
  
<body>
    <h1>Script failed to load.</h1>
    <p>Was the google closure compilation clean? If so...</p>
    <p>...please check the browser console.</p>
</body>
</html>
            
          
!
            
              .caution {
    background: #ff0;
    padding: 4px;
    border: 1px dashed #c5c5c5;
}

code {
    background: beige;
    padding: 1em;
}

.precode {
    font-family: 'Source Code Pro', monospace;
    background: #fcfcfc;
    border: 2px inset #aaa;
    padding: 1em;
    margin-right: 48px;
}

.precode i {
    /*background:#FaFaDd;*/
    color:blue;
}
.precode b {
    /*background:#FaFaDd;*/
    color:#003300;
    padding: 2px;
}
.precode strong {
    /*background:#FaFaDd;*/
    color:red;
    padding: 2px;
}

.techwrite {
    font-family: 'Source Sans Pro', sans-serif;
}

.narrativecol {
    flex: 30%;
    max-width: 300px;
    padding-left: 12px;
    padding-right: 12px;
}

/*html { overflow-y: scroll; }*/
html { margin-left: calc(100vw - 100%); }

.techtitular {
    /*font-family: 'Cabin', sans-serif;*/

    font-family: 'Lora', serif;

}
.techtitle {
    /*text-align:center;*/
    font-size:40px;
}

.techsubtitle {
    text-align:left;
    font-size:24px;
}

.techheader {
    text-align:left;
    font-size:18px;
    font-family: 'Source Sans Pro', sans-serif;
}
/*
First, a utility:
    function todoMatchesFilter( td, filter ) {
        return filter==="All"
            || (filter==="Active" && !td.completed)
            || (filter==="Completed" && td.completed);
    }

Now two solutions. The first selects which To-dos become LIs, so DOM actually
comes and goes. Change the UL kidValues formula in the 'yourturn' bit to be this:

        kidValues: cF(c => {
                        let f = fmK(c.md, "filters").selection;
                        return Todos.items.filter(td=>todoMatchesFilter(td, f));
                    })


The second solution adds/removes the hidden attribute selectively. Make this the first
parameter to the function TodoLI (in the 'yourturn' bit):
    {hidden: cF( c=> !todoMatchesFilter( td, fmK(c.md, "filters").selection))}


 */
            
          
!
            
              // ----------------------------------------
// --- driver app initialization ----------
cellsReset();

var categories = ['chat', 'code', 'main'];
var nubits = {};
categories.map( c=> nubits[c] = {});

var chats = {};
var sources = {};
var bitIds = ['preface', 'justhtml',
              'webco', 'dynodom', 'ktodo',
              'xhr', 'yourturn',
              'summary','scaling'];

var bits = new Array;

function defit (category, id, it) {
    if (!categories.includes(category))
        throw 'defbit> undefined category '+category;
    if (!bitIds.includes(id))
        throw 'defbit> undefined bit '+id;

    nubits[category][id] = it;
}

function getit (category, id, b) {
    if (!categories.includes(category))
        throw 'getit> undefined category ' + category;
    if (!bitIds.includes(id))
        throw 'getit> undefined bit ' + id;

    return nubits[category][id];
}

function defbit (id, b) { defit( 'main', id, b)}
function getbit( id) { return getit('main', id)()}

function defchat (id, b) { defit( 'chat', id, b);}
function getchat( id) { return getit('chat', id)}

function defcode (id, b) { defit( 'code', id, b);}
function getcode( id) { return getit('code', id)}

// ------------------------------------------------
// -------- The bits ------------------------------
// ------------------------------------------------

defbit('preface',
    ()=>{return {
            title: "Preface",
            notes: [
                "The last hundred lines of the source comprise the host application, itself a demonstration of mxWeb.",
                "Here is a complete <a target='_blank' href='https://github.com/kennytilton/webmx/tree/master/js'>" +
                            "TodoMVC</a> implementation.",
                "Pardon my CSS. And even my Javascript. I am a native Lisper.",
                "We have a ClojureScript version as well."],
            mxDom:
                [section({ class: "todoapp"},
                    header({class: "header"},
                        h1("todos"))),
                    center( "Coming soon, the app.")]
    }});

defbit('scaling',
    ()=>{return {
            title: "Prolog: Maturity? Scalability?",
            mxDom:  [h1("")]}});

defchat( 'scaling', "Yes and yes. Such software has been driving everything from Mac OS9 Quickdraw to Tcl/Tk to Gtk to OpenGL to Windows GDT to qooxdoo JS to HTML to PhoneGap for over twenty years.\
\n\
It has been used to build a complete 100kloc Common Lisp <a href='https://smuglispweeny.blogspot.com/2008/03/my-biggest-lisp-project.html'>clinical drug trial management system</a> and this 80kloc Common Lisp <a href='https://tiltonsalgebra.com'>Algebra tutorial</a>. And more.\
\n\
The Algebra system has over twelve hundred distinct rules, and on busy screens the AG can have over eleven hundred active nodes.\n\
Bugs in the dataflow engine are found less than once a year, partly because the engine is mature, partly because all code paths are heavily travelled.");

defbit('justhtml',
    ()=>{return {
        title: "An All-JS, HTML Work-alike. And fast.",
        notes: null,
        mxDom: [
        section({class: "todoapp"},
            header({class: "header"},
                 h1("todos"))),
        footer({class: "info"},
            [
                "Created by <a href='http://tiltontec.com'>Kenneth Tilton</a>",
                "Inspired by <a href='http://todomvc.com'>TodoMVC</a>"
            ].map(s => p({}, s)))
        ]
    }});

/// --- webco - Web Components -------------------------------
///

function credits (attrs, ...content) {
    return footer(Object.assign({}, {class: "info"}, attrs),
        // Look, Ma! No JSX! No toolchain! Standard JS....
        content.map( s => p({},s)));
}

defbit( "webco",
    ()=>{return {
        title: "Web Components Accompli",
        mxDom: [
        section({ class: "todoapp"},
            header({class: "header"},
                h1("todos"))),
        credits({style: "font-size:18px"},
            "Created by <a href='http://tiltontec.com'>Kenneth Tilton",
            "Inspired by <a href='http://todomvc.com'>TodoMVC</a>")]
    }});

class TodoList extends Model {
    constructor( titles ) {
        super( null, "TodoList",
            {
                items: cI( titles? titles.map( t=> new Todo(t)):[]),
                empty: cF( c=> c.md.items.length ===0),
                done: cF( c=> c.md.items.filter( td=> td.completed)),
                undone: cF( c=> c.md.items.filter( td=> !td.completed))
            });
        this.awaken();
    }
    add (td) {
        // if we mutate 'items', data flow internals will not see the change
        let newv = this.items.slice(0);
        newv.push( td);
        this.items = newv;
        return this;
    }
    delete (td) {
        // if we mutate 'items', data flow internals will not see the change
        let tdx = this.items.indexOf( td);
        if (tdx === -1) return;
        let is = this.items.slice(0);
        is.splice( tdx, 1);
        this.items = is;
        return this;
    }
}


var Todos;

function todoAddNewEZ (mx, e) {
    if (e.key === 'Enter') {
        let title = e.target.value.trim();
        e.target.value = null; // clear input either way

        if (title !== '') {
            Todos.add({
                title: title,
                completed: false
            });
        }
    }
}

function todoAppHeader ( newTodoHandler ) {
    return header({class: "header"},
                h1("todos"),
                input({
                    class: "new-todo",
                    autofocus: true,
                    placeholder: "Type an item to do and hit Return.",
                    onkeypress: newTodoHandler
                }));
}

function todoDashboardEZ ( ...plugins ) {
    return footer({ class: "footer",
                    hidden: cF(  c => Todos.empty )},
            span({ class: "todo-count"},
                 { content: cF(c => {
                                let remCt = Todos.undone.length;
                                return `${remCt} item${remCt === 1 ? '' : 's'} remaining`;
                    })}),
        (plugins || []).map( p => p())
    );
}

/// dynodom - DOM driven by data flow --------------------

defbit("dynodom",
    ()=>{return {
        title: "Enter Data Flow",
        notes: ["To-do LIs are all regenerated to accommodate one new to-do. We fix that shortly.",
            "Component functions break up the code as well as offer re-use."],
        initFn: ()=> Todos = new TodoList,
        mxDom: [
            section({class: "todoapp"},
                todoAppHeader( todoAddNewEZ),
                section({
                        class: "main",
                        hidden: cF(c => Todos.empty)
                    },
                    ul({class: "todo-list"},
                            c => Todos.items
                                    .map(td => li({style: {padding: "9px"}},
                                            td.title)))),
                todoDashboardEZ())]
    }});

// ----------------------------------------------------------
// --- ktodo - To-do gets its own data flow properties ------

class Todo extends Model {
    constructor( title ) {
        super( null, null,
            {
                title: title, // no editing this version
                completed: cI( false)
            });
            }
    delete () {
        Todos.delete( this);
    }
}

function todoAddNewBetter (mx, e) {
    if (e.key !== 'Enter') return;
    let title = e.target.value.trim();
    if (title !== '') {
        Todos.add( new Todo( title));
    }
    e.target.value = null;
}

function todoLI( attrs, c, todo, extras) {
    return li( Object.assign( { class: cF(c => (todo.completed ? "completed" : null))}, attrs),
            { todo: todo},
            div({class: "view"},
                input({ class: "toggle",
                        type: "checkbox",
                        checked: cF( c=> todo.completed),
                        onclick: ()=> todo.completed = !todo.completed})
                , label({ content: todo.title })
                , extras? extras( c, todo) : null
                , button({ class: "destroy",
                            onclick: ()=> todo.delete()})))
}

function clearCompleted () {
    return button({ class: "clear-completed",
                    hidden: cF(c=> Todos.done.length === 0),
                    onclick: mx => Todos.done.map( td=> td.delete())},
            "Clear completed");
}

defbit('ktodo',
    ()=>{return {
        title: "To-Do properties join the data flow",
        initFn: ()=> {
            Todos = new TodoList(["Wash car"]);
        },
        mxDom: [
            section({class: "todoapp"},
                todoAppHeader( todoAddNewBetter),
                section({ class: "main",
                            hidden: cF( c=> Todos.empty)},
                    ul({class: "todo-list"},
                        c => Todos.items.map(td => todoLI( {}, c, td )))),
                todoDashboardEZ(clearCompleted))]
    }});

// --- xhr ---------------------------------------------------------

defbit('xhr',
    ()=>{return {
        title: "XHR joins the data flow",
        notes: [
            "The JS mxXHR lift into the Matrix was hacked just enough to support this panel.",
            "The 'kidValues' mechanism avoids rebuilding existing DOM and even proxies."],
        initFn: ()=> {
            Todos = new TodoList(["adderall", "Yankees"]);
        },


        mxDom: [
            section({class: "todoapp"},
                todoAppHeader( todoAddNewBetter),
                section({
                        class: "main",
                        hidden: cF( c=> Todos.empty)
                    },
                    ul({class: "todo-list"},
                        {
                            kidValues: cF(c => Todos.items),
                            kidKey: k => k.todo,
                            kidFactory: (c,td) => todoLI({}, c, td, aeAlertGI)
                        },
                        c => c.kidValuesKids())),
                todoDashboardEZ(clearCompleted))]
    }});

function aeBrandURI (brand) {
    return `https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:${ brand }&limit=3`
}

function aeAlertGI ( c, todo ) {
    return i( {
                class: "aes material-icons md-36",
                hidden: cF( c=> c.md.aeInfo===null),
                style: cF(  c => { return { display: Todos.empty? "none":"block",
                                    font_size: "36px",
                                    color: "red",
                                    background: "white"}}),
                onclick: mx => alert( mx.aeInfo),
                },
        {
            lookup: cF( c=> new mxXHR( aeBrandURI( todo.title), {
                send: true,
                delay: 500 + Math.random(5)*1000})),

            aeInfo: cF( function (c) {
                let xhr = c.md.lookup.xhr;
                if ( xhr) {
                    if (xhr.status === 200) {
                        let obj = xhr.response;
                        return obj.meta.results.total + " Adverse Events found on FDA.gov";
                    } else {
                        return null;
                    }
                } else {
                    return null;
                }
            })
        },
        "warning")
}

function todoMatchesFilter( td, filter ) {
    return filter==="All"
        || (filter==="Active" && !td.completed)
        || (filter==="Completed" && td.completed);
}

function fmK( from, className, how) {
    return from.fmUp( mx=>mx.class === className)
}

defbit('yourturn',
    ()=>{return {
        title: "Your turn!",
        notes: null,
        initFn: ()=> {
            Todos = new TodoList(["adderall", "Yankees",
                                  "Visine", "probiotics", "echinacea"]);
        },

        mxDom: [
            section({class: "todoapp"},
                todoAppHeader( todoAddNewBetter),
                section({ class: "main",
                        hidden: cF( c=> Todos.empty)},
                    ul({class: "todo-list"},
                        c => {
                            let f = fmK(c.md, "filters").selection;
                            return Todos.items
                                        .map( td=> todoLI( {}, c, td))
                        })),
                todoDashboardEZ( todoFilters, clearCompleted))]}});

function todoFilters () {
    return ul({class: "filters"},
            {name: "filters", selection: cI("All")},
        ['All', 'Active', 'Completed']
            .map(state => li(b({
                    class: cF(c => c.md.selected ? "selected" : ""),
                    onclick: mx => fmK(mx, "filters").selection = state
                },
                {
                    selected: cF(c => fmK(c.md, "filters").selection === state),
                    content: state
                }))))
}
// ---------------------------------------------
// --- Summary ---------------------------------

defbit('summary',
    ()=>{return {
        title: "Summary: The Developer Experience",
        notes: null,
        code: null,
        mxDom:
            [
                section({ class: "todoapp"},
                    header({class: "header"},
                        h1("mxWeb"))),
                credits({style: "font-size:18px"},
                    "Created by <a target='_blank' href='mailto:ken@tiltontec.com'>Kenneth Tilton</a>",
                    "Part of the <a href='https://github.com/kennytilton/matrix/blob/master/js/matrix/readme.md'>Matrix System</a>")]
    }});


// --------------------------------------------------------------------
// ----- Text Content -------------------------------------------------

/// --- Your turn --------------------------


defchat( 'yourturn', "Now it is your turn to try \
programming with data flow. You will notice some additions to the dashboard: widgets \
'All', 'Active', and 'Completed'. As you click them, they become highlighted in \
radio group fashion. But nothing else happens.\
\n\
Your mission is to make something else happen, namely, change which to-dos appear as the filter \
changes. The code you need to change is the 'mxDom' property defined \
in the code that begins \"defbit('yourturn'...\". The pen includes the \
'matches' predicate shown below, as well as the code implementing \
the radio group effect. That contains the clues you need to complete the task.\
\n\
Some help: First, FYI, 'fmK' searches the Matrix tree (family, hence 'fm') for an element with the given \
class. That should just work for you.\
\n\
Second, hidden in the CSS of the pen are two solutions. One works via the hidden attribute on LIs, \
the other works by filtering the to-dos before generating the LIs.\
\n\
Good luck! If you need help, send <a target='_blank' href='mailto:ken@tiltontec.com'>me</a> a note.");

defcode( 'yourturn', "\
function todoMatchesFilter( td, filter ) {\n\
    return filter==='All'\n\
        || (filter==='Active' && !td.completed)\n\
        || (filter==='Completed' && td.completed);\n\
}\n\
\n\
function todoFilters () {\n\
    return ul({class: 'filters'},\n\
            ['All', 'Active', 'Completed'].map( \n\
                state => li( b( { class: cF(c => c.md.selected ? 'selected' : ''),\n\
                                  onclick: mx => { mx.fmK('filters').selection = state}},\n\
                                { selected: cF(c => c.md.fmUp( 'app').selection === state),\n\
                                  content: state}))))\n\
}");


defchat( 'preface',
    "Welcome to the development of an application within an application, each built \
with mxWeb, a Web un-framework* consisting of just JS, HTML, and CSS running within a \
fine-grained data flow system we call Matrix.\
\n\
* No framework?! Oddly, once we have data flow we need nothing else. You will see.\
\n\
The application developed will cover half the classic \
<a target='_blank' href='https://github.com/tastejs/todomvc/blob/master/app-spec.md'>TodoMVC spec</a> and \
appear live above.\
\n\
My focus will be the developer experience, but inquiring minds will wonder what is going on \
behind the scenes. <a target='_blank' href='https://github.com/kennytilton/matrix/blob/master/js/matrix/readme.md'>\
This will help.</a>\
\n\
Please check the notes below, then hit 'Next' above to get started.");

defcode( 'preface',
    "All tag functions have the signature:\n\
  <i>tag</i>([<i>HTML attributes</i>, [<i>custom properties</i>,]] <i>children*</i>)\n\
\n\n\
section({class: 'todoapp'},\n\
   header({class: 'header'},\n\
      h1('todos'))),\n\
\n\
   p('The working app will appear here.')");

/// --- justhtml ----------------------------------------------------------------------

defcode('justhtml',
    "section({class: 'todoapp'},\n\
       header({class: 'header'},\n\
          h1('todos'))),\n\
    \n\
    footer({class: 'info'},\n\
       ['Created by &lt;a href='http://tiltontec.com'&gt;Kenneth Tilton', \n\
        'Inspired by &lt;a href='http://todomvc.com'&gt;TodoMVC</a>']\n\
        .map( s => p({},s)))"
);

defchat('justhtml',
    "A design imperative of mxWeb is to work so much \
like HTML that graphic designers can write it.\
\n\
Where we come up short, please file an RFE.\n\
\n\
mxWeb is also developer-friendly: we just code JS.\
\n\
As for speed, the point granularity of the data flow means \
we can make point DOM updates, avoiding VDOM and diffing.\
\n\
Turn on 'DOM Logging' in our toolbar and open the JS console to track the action."
);

/// --- webco - web components -------------------------------------------------------

defcode("webco", "\
function credits (attrs, ...content) {\n\
    return footer(Object.assign({}, {class: 'info'}, attrs),\n\
        content.map( s => p({},s)));\n\
}\n\n\
section({ class: 'todoapp'},\n\
   header({class: 'header'},\n\
      h1('todos'))),\n\
credits({style: 'font-size:18px'},\n\
   'Created by &lt;a href='http://tiltontec.com'&gt;Kenneth Tilton',\n\
   'Inspired by &lt;a href='http://todomvc.com'&gt;TodoMVC&lt;/a&gt;'])");

defchat("webco",
    "Since we just code JS, developing a custom HTML element is as easy as writing a function. \
That function can take as many parameters as needed to support reuse. \
\n\
With the same reuse objective, <a target='_blank' href='https://developer.mozilla.org/en-US/docs/Web/Web_Components'>Web Components</a> look \
promising, but JS functions will be hard to top. \
\n\
The function 'credits' in the code below is a trivial example. More interesting cases follow.");


// -------------------------------------------------------------------------------------
// -------------  dynodom --------------------------------------------------------------

defcode('dynodom', "\
Todos = mkm( null, 'Todos', {\n\
            items: cI( []),\n\
            <b>empty: cF( c=> <i>c.md.items</i>.filter( td=> !<i>td.deleted</i>).length ===0)</b>\n\
        })\n\
\n\
// the 'main' for this panel....\n\
    \n\
section({class: 'todoapp'},\n\
  todoAppHeader( todoAddNewEZ),\n\
    section({\n\
            class: 'main',\n\
            <b>hidden: cF(c => <i>Todos.empty</i></b> )\n\
        },\n\
        ul({class: 'todo-list'},\n\
            c => <i>Todos.items</i>\n\
                .map(td => li({style: {padding: '9px'}},\n\
                              td.title)))),\n\
    todoDashboardEZ())\n\
\n\
function todoAddNewEZ (mx, e) {\n\
    if (e.key === 'Enter') {\n\
        let title = e.target.value.trim();\n\
        e.target.value = null; // clear input either way\n\
\n\
        if (title !== '') {\n\
            // concat forces new array so Matrix detects change \n\
            <strong>Todos.items = <i>Todos.items</i>.concat({\n\
                title: title,\n\
                completed: false,\n\
                deleted: false\n\
            })</strong>;\n\
        }\n\
    }\n\
}\n\
\n\
function todoAppHeader ( newTodoHandler ) {\n\
    return header({class: 'header'},\n\
                h1('todos'),\n\
                input({\n\
                    class: 'new-todo',\n\
                    autofocus: true,\n\
                    placeholder: 'Type an item to do and hit Return.',\n\
                    onkeypress: newTodoHandler\n\
                }));\n\
}\n\
\n\
function todoDashboardEZ ( ...plugins ) {\n\
    return footer({\n\
            class: 'footer',\n\
            <b>hidden: cF( c => <i>Todos.empty</i>)</b>},\n\
        span({ class: 'todo-count'},\n\
            {<b>content: cF(c => {\n\
                let remCt = <i>Todos.items</i>.filter(todo => !(<i>todo.completed</i> || <i>todo.deleted</i>)).length;\n\
                return `${remCt} item${remCt === 1 ? '' : 's'} remaining`;</b>\n\
            })}),\n\
        (plugins || []).map( plug => plug())\n\
    );\n\
}");

defchat( "dynodom", "\
And now data flow: a change to the model triggers \
changed view content, including new DOM elements. \
\n\
A new to-do requires a new LI element. The first to-do requires a dashboard \
be unhidden. The dashboard shows a count of the items.\
\n\
The app within the app is live. Try adding a to-do, if you like. \n\
\n\
Note the transparency with which data flow is accomplished. Well, you \
cannot: it is transparent. See the glossary for how we highlighted the implicit pub/sub.\
\n\
As promised, our components have gotten more interesting. One accepts a custom event\
handler, and the dashboard accepts optional plugin widgets (not yet leveraged).");

defchat('ktodo', "To-dos now have individual data flow properties, \
and a fancier LI where those properties can be manipulated.\
\n\
We pre-loaded a to-do for you. Feel free to add more.\
\n\
Toggle to-do completion with the faint circle to its left. \
Look for its styling to change. Look for 'items remaining' to change \
and for 'Clear completed' to come and go from the dashboard. That is a working button. \
Give it a go, if you like.\
\n\
The spec says to hide the dashboard if there are no items. \
Watch for the dashboard to disappear when you delete the last remaining item.\n\
\n\
When you hover over a to-do, a red 'X' appears to the far right. Click that to \
permanently delete a to-do item. Keep an eye on 'items remaining'.\
\n\
As an exercise, try to follow the declarative data flow chain of each behavior described.");

defcode('ktodo', "\
class Todo extends Model {\n\
    constructor( title ) {\n\
        super( null, null,\n\
            {\n\
                title: title,\n\
                completed: cI( false),\n\
                deleted: cI( false)\n\
            });\n\
    }\n\
}\n\
\n\
function todoLI( c, todo) {\n\
  return li({ <b>class: cF(c => (<i>todo.completed</i> ? 'completed' : null))}</b>,\n\
    div({class: 'view'},\n\
        input({\n\
            class: 'toggle',\n\
            type: 'checkbox',\n\
            <b>checked: cF( c=> <i>todo.completed</i>),</b>\n\
            <strong>onclick: ()=> todo.completed = !todo.completed}</strong>)\n\
\n\
        , label({ content: todo.title})\n\
\n\
        , button({ class: 'destroy',\n\
                   <strong>onclick: ()=> todo.deleted = true</strong>})));\n\
}\n\
\n\
function clearCompleted () {\n\
    return button({ class: 'clear-completed',\n\
                    <b>hidden: cF(c => !<i>Todos.items</i>.filter(td => <i>td.completed</i>).length)</b>,\n\
            onclick: mx => Todos.items\n\
                             .filter( td => td.completed )\n\
                             .map( <strong>td => td.deleted = true</strong>)},\n\
        'Clear completed');\n\
}");

defchat('xhr', "Callback Hell? In the imperative paradigm, yes.\n\
\n\
Not in the data flow paradigm. Data flow exists to propagate new inputs gracefully \
 to dependent application state, so asynchronous XHR completion handlers fit right in.\
\n\
We evince this with a random fake delay of up to several seconds. Whenever the \
request returns, the response handler simply assigns the response to the \
appropriate input Cell. Matrix internals handle the rest.\
\n\
In this example, we pointlessly look up each to-do title in the \
FDA.gov adverse events database. If you see the warning icon, give \
it a click.\
\n\
The FDA.gov search endpoint is aggressive about matching, so 'Wash car' will find results. \
And all drugs have adverse events, so do not be concerned by <i>any</i> results.\
\n\
This is a trivial callback scenario, but the data flow solution does scale. \
Here is my <a target='_blank' href='https://github.com/kennytilton/xhr/blob/master/cljs/xhr/XHR.md'>\
original investigation</a> into complex XHR via data flow.");


// --- xhr --------------------------------------------------------
defcode('xhr', "\
class mxXHR extends Model {\n\
    constructor( uri , options) {\n\
        super( null, 'mxXhr',\n\
            { uri: cI( uri),\n\
              xhr: cI( null)});\n\
    }\n\
\n\
    send( delay) {\n\
        let mxx = this;\n\
        goog.net.XhrIo.send( mxx.uri, function(e) {\n\
            withChg('xhrResult', ()=> <strong>mxx.xhr = e.target</strong>);\n\
        });\n\
        return mxx;\n\
    }\n\
}\n\n\
section({class: 'todoapp'},\n\
   todoAppHeader( todoAddNewBetter),\n\
   section({ class: 'main',\n\
             <b>hidden: cF(c => <i>Todos.empty</i>)</b>},\n\
      ul({ class: 'todo-list'},\n\
         { <b>kidValues: cF(c => <i>Todos.items</i>)</b>,\n\
           kidKey: k => k.todo,\n\
           kidFactory: (c,td) => todoLI({}, c, td, aeAlertGI)},\n\
        <b>c => <i>c.kidValuesKids()</i>)</b>),\n\
      todoDashboardEZ(clearCompleted))\n\
\n\
function aeAlertGI ( c, todo ) {\n\
    return i( { class: 'aes material-icons md-36',\n\
                style: 'font-size:36px;color:red;background:white',\n\
                <b>hidden: cF( c=> !<i>c.md.aeInfo</i>)</b>,\n\
                onclick: mx => alert( mx.aeInfo)},\n\
              { <b>lookup: cF( c=> new mxXHR( aeBrandURI( <i>todo.title</i>),\n\
                                           { send: true,\n\
                                             delay: 500 + Math.random(5)*1000}))</b>,\n\
    \n\
                <b>aeInfo: cF( function (c) {\n\
                    let <i>xhr = c.md.lookup.xhr</i>;\n\
                    if ( xhr) {\n\
                        if ( xhr.isSuccess() ) {\n\
                            let obj = xhr.getResponseJson();\n\
                            return obj.meta.results.total + ' Adverse Events found on FDA.gov';\n\
                        } else {\n\
                            return null;\n\
                        }\n\
                    }\n\
                })</b>},\n\
           'warning')\n\
}\n\
\n\
function aeBrandURI (brand) {\n\
    return `https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:${ brand }&limit=3`\n\
}");


/// ------------------------------------------
/// --- Summary ------------------------------

defchat( 'summary',
    "All submissions to TodoMVC.com offer the same functionality, and most \
involve some reactive mechanism.\
\n\
The developer experience separates them.\
\n\
mxWeb requires only JS . No limits on expressiveness, no toolchain, yes rapid iteration.\
\n\
It is an un-framework, involving only thinly wrapped HTML and CSS. \
<a target='_blank' href='https://developer.mozilla.org/en-US/'>MDN</a> provides the reference manual.\
\n\
The reactive element so essential to UI development is transparent; just read \
and set properties normally and data flow emerges. \
mxWeb's prime objective is that the developer not have to think much about mxWeb.\
\n\
mxWeb draws us into building up that application in \
small semantic chunks, naturally decomposing complex UIs into simple, declarative formulas. \
Formulas refer freely to values from view, model, local storage, or the web. \
\n\
Why does a seamless developer experience matter?\
\n\
UI/UX programming involves more refactoring than original coding. No one knows how an interface feels \
until we try it. And then the requirements change, or the product succeeds and the requirements grow. \
Easier development means more time and energy for refactoring, and that means better UXes.\
\n\
If interested in this or the CLJS version, send <a target='_blank' href='mailto:ken@tiltontec.com'>me</a> a note");

// --- The driver app -----------------------------------------------
// ------------------------------------------------------------------
// --- we "lift" localStorage into the Matrix. To a degree. ---------

const currBitNo = cFI( c=> {
        let r = window.localStorage.getObject("CPMatrixTodo.bit");
        //clg('local bit no ', r);
        return r === null ? 0 : (r < 0? 0: (r >= bitIds.length? (bitIds.length - 1): r));
    },
    // we use an observer to persist the current "bit" number so page reloads pick up where we left off
    { observer: (n, md, newv ) => window.localStorage.setObject("CPMatrixTodo.bit", newv)});

// -------------------------------------------------------------------------------------
// --- Main ----------------------------------------------------------------------------

function CPMatrixTodo () {
    return [
        p({class: 'techtitular techtitle'}, "Intro to Matrix and mxWeb"),
        toolbar(),
        div( c=> bitAssemble( bitIds[currBitNo.v]))
        //toolbar()
    ];
}

window['CPMatrixTodo'] = CPMatrixTodo;

function codeGlossary() {
    return div( {style: "padding-left:12px;background:#f5f5f5"},
        ul( {class: "precode", style: "border:none;list-style:square;background:none"},
            [span("'cI' creates an input Cell"),
                span("'cF' creates a formulaic Cell"),
                span("'mkm' makes a model (object with cells for properties)"),
                i("Code that 'subscribes' to other data"),
                b("Code that computes derived data"),
                strong("Event code that feeds outside data into the Matrix flow"), "These code chunks get out of date. Check the source if in doubt."].map( g=> li(g))))
}

function bitAssemble( bid) {
    let codeString = getcode( bid),
        chat = getchat( bid),
        b = getbit( bid);

    if ( b.initFn) {
        b.initFn();
    }
    return [
        div( b.mxDom),
        p( {class: 'techtitular techsubtitle'}, b.title),
        newsprint( chat),
        b.notes? div( p({class: 'techheader'}, "Nota bene"),
            ul( {class: "techwrite",
                    style: "list-style:square"},
                b.notes.map( note=> li( {style: {margin_bottom: "6px"}},
                    note)))): null,

        codeString? [ div( p({class: 'techheader'}, "Code Highlights (glossary below)"),
            pre({class: 'precode'}, codeString)),
            div( p({class: 'techheader'}, "Code Glossary"),
                codeGlossary())] : null
    ];
}

function newsprint( text) {
    /*
    This is a great example of a custom Web component.
    Not so much the quickly hacked implementation, but
    the idea itself of filling a void in HTML (flowing
    text into columns like a newspaper) with a function
    which, once evolved, becomes a permanent asset. And
    it just yields standard HTML/CSS. And no preprocessor
    is required.
     */
    if (!text) return p("");
    let pgs = text.split("\n"),
        brk = null;

    for ( let n =0, chars = 0; n < pgs.length; ++n) {
        chars += pgs[n].length;
        if ( chars > text.length * 0.40) {
            brk = ++n;
            break;
        }
    }

    return div( {style: {display: "flex",
            flex_direction: "row"},
            class: "techwrite"},
        div({class: "narrativecol"},
            pgs.slice(0, brk).map( pgr => p(pgr))),
        div({class: "narrativecol",
                style: "border-left: 1px solid #aaa;"},
            pgs.slice(brk).map( pgr => p(pgr))));
}

function toolbar () {
    return div({
            style: {background: "#fdfdfd",
                margin_left: "24px",
                width: "440px",
                display: "flex",
                flex_direction: "row",
                align_items: "center"}},
        controls)
}

var controls = [
    button({class: cF( c=> "pure-button " +  ( c.md.disabled ? "pure-button-disabled":"")),
            style: "margin-left:18px",
            disabled: cF( ()=> currBitNo.v <= 0),
            onclick: c=> --currBitNo.v},
        "Back"),
    div( {style: "margin:8px"}, nTabs( bitIds.length)),
    button({class: cF( c=> "pure-button " +  ( c.md.disabled ? "pure-button-disabled":"")),
            disabled: cF( c=> currBitNo.v >= bitIds.length - 1),
            onclick: c=> ++currBitNo.v}
        , "Next"),
    input({
        id: "logToggle",
        type: "checkbox",
        checked: domLogging,
        onchange: (mx,e) => domLogging = e.target.checked,
        style: "margin-left:24px;margin-right:9px"
    }),
    label(
        { for: "logToggle",
            title: "open the JS console to see logging of all DOM manipulation."},
        "DOM logging")];


function nTabs (n) {
    tabs = [];
    for( let i=0; i < n; ++i) {
        let ii = i;
        tabs.push( button( {onclick: ()=> currBitNo.v = ii,
            style: cF( c=>"margin-left:8px;background-color:"
                + (ii===currBitNo.v? "cyan":""))}, ""+i));
    }
    return tabs;
}


document.body.innerHTML =  tag2html( CPMatrixTodo());


            
          
!
999px
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Console