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seethrough is a simple XML/XHTML template engine for Erlang.

Please note: seethrough has progressed a bit since the examples below were written. While they still hold, they don’t represent all the features.

Example Input


<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:e="http://hyperstruct.net/seethrough">
  <head>

    <title e:content="title"/>
  </head>
  <body>
    <h1 e:content="title"/>

    <h2>
      <e:attr name="style">font-weight: bold;</e:attr>

      <e:attr name="align"><span e:replace="alignment"/></e:attr>
      <e:attr name="bgcolor" value="background_color"/>
      <span e:replace="subtitle"/>
    </h2>

    <div e:condition="error">

      There was an error processing this directive.
    </div>

    <table>
      <thead>
        <tr>
          <th>Address</th>

          <th>Name</th>
        </tr>
      </thead>
      <tbody>
        <tr e:repeat="crew">

          <td e:content="address"/>
          <td e:content="name"/>
        </tr>
      </tbody>
    </table>
  </body>

</html>

Example Processing


test() ->
    io:format(
      seethrough:apply_template("test.html",
          [{title, "Space"},
           {alignment, "center"},
           {subtitle, {?MODULE, get_subtitle, []}},
           {background_color, "blue_skies"},
           {crew, {? MODULE, get_crew, []}}])).

get_subtitle() ->
    "The final frontier...".

get_crew() ->

    [[{address, "kirk@enterprise.glx"},
      {name, "Jim"}],
     [{address, "spock@enterprise.glx"},
      {name, "Spock"}],
     [{address, "mccoy@enterprise.glx"},
      {name, "Doc"}]].

Example Output


<?xml version="1.0"?>
<html xmlns:e="http://dev.hyperstruct.net/seethrough" xmlns="http://www.w3.org/1999/xhtml">
  <head>

    <title>Space</title>
  </head>
  <body>
    <h1>Space</h1>

    <h2 style="font-weight: bold;" align="center" bgcolor="blue_skies">

      The last frontier...
    </h2>

    <table>
      <thead>
        <tr>

          <th>Address</th>
          <th>Name</th>
        </tr>
      </thead>
      <tbody>

        <tr>
          <td>kirk@enterprise.glx</td>
          <td>Jim</td>
        </tr><tr>

          <td>spock@enterprise.glx</td>
          <td>Spock</td>
        </tr><tr>
          <td>mccoy@enterprise.glx</td>

          <td>Doc</td>
        </tr>
      </tbody>
    </table>
  </body>

</html>

Caching

If you’re going to render the same template over and over, passing
different data each time, you’ll want to do the parse/compile step
only once, keep the result around, and use that for rendering.


%% Parsing
{XMLTree, _Misc} = xmerl_scan:file(File),
Intermediate = seethrough:visit(XMLTree),

%% Rendering intermediate form within Env1
Render1 = seethrough:render(Intermediate, Env1),
xmerl:export_simple(lists:flatten([Render1]), xmerl_xml,
                    [#xmlAttribute{name = prolog, value = ""}]).

%% More rendering, but within Env2
Render2 = seethrough:render(Intermediate, Env2),
xmerl:export_simple(lists:flatten([Render2]), xmerl_xml,
                    [#xmlAttribute{name = prolog, value = ""}]).

%% Yet more rendering, within Env3
Render3 = seethrough:render(Intermediate, Env3),
xmerl:export_simple(lists:flatten([Render3]), xmerl_xml,
                    [#xmlAttribute{name = prolog, value = ""}]).

Supported tags

e:attr
e:include

Supported attributes

e:content
e:replace
e:repeat
e:condition

Notes

seethrough does not depend on any framework, just plain old
result = fn(args), so it should be very easy to use it in
any context you want.

At less than 200 lines of actual code, it should also be pretty
hackable.

seethrough is released under the BSD license.

Last edited by bard, Sun Oct 05 09:47:15 -0700 2008

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