Google Books and the Three-Fold Path

News:

This NY Times article contains an excellent set of links to the pro and con positions re the settlement of authors and publishers v. Google. (The settlement will a: liberate books, or b: obliterate books say those who support or oppose it. I'm betting on c: boost books' Google search rankings.)

The Three-Fold Path to HTML Documents.

I have just released my first serious Ruby plugin for Google SketchUp. It is useful for creating multi-scene animations of a 3D model. Any non-trivial SketchUp Ruby UI is shown as a page in a browser, an HTML document. Here are the alternatives for creating an HTML document.

HTML

First, there is HTML, a simple set of markup commands that are the cyberspace equivalent of typesetting instructions. Let's look at a sample:

<table align=center bgcolor=#fofoff border=1>
    <tr>
        <th>Heading, column one</th>
        <th>Heading, columne two</th>
    </tr>
    ...
</table> 

The basics are a set of tags that come in <tag> ... </tag> pairs. Here you see table, table row, and table heading tags. Omitted are the table datum ( <td> ... </td>) tags that will be part of the additional rows that provide the table's contents. These tags can have embedded attributes. Here the table is centered, its background set to light blue and border set to one pixel wide. Other tags imply attributes. Table heading cells default to centered and boldface.

If you decide to learn basic HTML, to improve your blog posts, for just one example, my easyHTMLtutorial.com will get you up and running quickly. HTML is simple. It's also the underpinning of the second path to HTML documents.

JavaScript: document.write()

There are times when you leave the simplicity of HTML and use JavaScript programming to create your HTML customized to your viewer's data. My Ruby is one example: it creates a table of checkboxes based on the user's model. There is one row for each "layer" (grouping of model components) and one column for each "scene" in the animation. It can only be created after querying the user's model for, for example, a list of the names of each layer. JavaScript for my Ruby's table would look like this:

// query model for data
// construct a "model" object from the results
document.write( '<table align=center bgcolor=#fofoff border=1>' );
document.write( '<tr>' );
for ( var i = 0; i < model.scenes.length; i++ ) {
    document.write( '<th>' + model.scenes[i].name + '</th>' );
} 
...

This uses JavaScript's document.write() method to write HTML into the page. It is not as simple as plain HTML but it lets your UI be tailored to the users' specifics. In this case, it is writing as many column headings as the user has scenes in his model, using names read from the model. At a cost of one level of indirection, this creates a web page tailored to the user's data. Unfortunately, it is not always an option.

DOM scripting

In my Ruby, for reasons I'll skip here, document.write() was not an option. While technically, simple document.write() calls are a form of DOM scripting (Document Object Model), there is another, less simple, low level at which you can create a web page.

Each web page is a set of objects attached to the "document" object, or attached to other objects which are, in turn attached to the document. In our table example, the table is attached to the document. The table row is attached to the table and the table headers are attached to the table row. Skipping lots of details, the basic idea is this:

var table = document.createElement( 'table' );
// set table attributes here
document.appendChild( table );
var row = table.insertRow();
head = document.createElement( 'th' );
head.innerHTML = 'The Column Heading Text';
row.appendChild( head );
...

Working at this very low level, your JavaScript is in total command. The cost: the simplicity of HTML is gone. If you have to drop to this bottom level, the amount and cost of the JavaScript rises dramatically. Switching from document.write() to bottom level DOM scripting was one of the reasons my two-week Ruby project took six weeks to complete.

"We don't go here unless we need to. Right, Monty?" Monty, my pet python, doesn't hear me. He's busy playing with the kitten.