[ANN] yhtml plugin

Rails
1

I have released a yhtml plugin, which is available at
http://http://svn.visualjquery.com/admin_console/trunk/admin_console/vendor/plugins/yhtml

You can also get my other plugins, specificlly: the pre-alpha
administrative console (AJAX-based scaffolding engine),
acts_as_automatic, which allows you to define associations in a single
yaml file, and not need to define has_many, has_one, belongs_to, or
acts_as_list at
http://svn.visualjquery.com/admin_console/trunk/admin_console/vendor/plugins/

Incidentally, the code in the plugins directly is my own, with the
exception of the Engines plugin, which is needed for the admin console
engine, as well as file_column, which I stuck in the engine to provide
future file_column support. The time_select lib that I included in the
admin console plugin is cannibalized from a number of sources, but is
substantially my own.

The yhtml plugin adds a rendering engine based on yaml.

Example yhtml

NOTE: The controller defines @hello as “- Title”

  • html:
    • head:
      • title: My Title <%= @hello %>
      • style: |
        body { font-family: verdana, sans-serif }
        p { font-weight: bold }
        li { list-style-type: none }
    • body:

Result from the yhtml renderer

My Title - Title body { font-family: verdana, sans-serif } p { font-weight: bold } li { list-style-type: none }
  • Text
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
  <li>5</li>
  <li>6</li>

  <li>7</li>
  <li>8</li>
  <li>9</li>
  <li>10</li>
  <li>Text</li>
  <li class="One T." id="Two" style="height: 30px; width:

20px">LI

  <li>
    <img

src=“http://ec1.images-amazon.com/images/G/01/nav2/images/skins/teal/logo-on.gif”
/>


Some More Text




    <td>12</td>
  </tr>
  <tr>
    <td>21</td>
    <td>Sat Jul 15 23:09:43 Eastern Standard Time 2006</td>
  </tr>
</table>

Discussion

The yhtml parser converts the hash returned by the YHTML parser into a
tree of YamlNodes.

A YamlNode contains:

  • A tag name (html, body, head, li, etc.)
  • Text contents
  • Parameters
  • Children that are YamlNodes

The parser then recursively parses the YamlNode tree, creating HTML with
appropriate indents.

You can put plain text into the YAML, which will not be parsed, by using
YAML’s “|” operator
for literals. The example above uses the operator.

Limitation

A YamlNode cannot contain both plain-text contents and child YamlNodes.
At the moment, this
will cause strange issues. If you want plain text and child nodes, wrap
the text in span, or
other tags. This limitation will be resolved in a future version.

The limitation is the result of the fact that the parser stores content
as an attribute, and
children as another (to make the recursive parsing easier), so the HTML
builder has no way of
knowing where in the list of children to put the content.

11
2

I have released a yhtml plugin, which is available at

Don’t take this the wrong way, but I have to ask … what’s the use-case
for
this?

Just curious, thanks.

3

Brittain wrote:

I have released a yhtml plugin, which is available at

Don’t take this the wrong way, but I have to ask … what’s the use-case
for
this?

Just curious, thanks.

First up, it was an excercise in (and an example of) a simple
alternative renderer, as well as using a recursive function to generate
HTML-like structures.

Second off, the resulting template is a far sight more readable than
regular HTML, because it enforces sane indenting, and doesn’t require
closing tags. In essence, the YAML template is a good representation of
a node-map in the HTML tree, which I think can be pretty useful
sometimes.

The plugin also generates much cleaner HTML than the normal rhtml
templates, because it automatically indents raw text (by converting line
breaks in literals into properly indented line-breaks), and because of
the indenting strictness, it’s very easy to create nice-looking,
well-indented HTML.

It also makes it much harder to create non-validating HTML (although
it’s certainly still possible to put things in contexts they don’t
belong). I forsee future versions of this project doing things that the
helpers already do (like adding alt’s in images that don’t have them and
what have you).

The bottom line is this: It was mainly a proof of concept (for myself
more than anyone) but the format definitely has its advantages.

4

Yehuda K. <wycats@…> writes:

The bottom line is this: It was mainly a proof of concept (for myself
more than anyone) but the format definitely has its advantages.

Gotcha, nice work. Thanks.

5

I love it how people start to think the same.

I’ve been working the last couple months on HAML which is not YAML
but is something similar in spirit to what you’ve created here, with a
few major differences in semantics.

I’ve applied to RailConf Europe to do a presentation revealing HAML,
so we’ll see when it gets released.

I’m just glad to see that I’m not the only one who is sick and tired
of living in 1996 with all the inline-html rendering. Beautiful markup
is not just a last-minute detail!

-hampton.