H2o hacking guide

1. argument parsing example

H2o hacking guide 

argument parsing.
=====================

 * variable name turns to ":variable" which uses ruby symbol style string to indicate if its a variable and to speed up context lookup
 * arguments are seperated by comma 
 * anything looks like named argument(name: "peter", age: 18) will parse into a option style array

H2o_Parser::parseArguments("variable")
// outputs ':variable'

H2o_Parser::parseArguments('person | speak "hello world", time: "today"')
// outputs array(':person', array(':speak', '"hello world"', array('time'=>'"today"')


context lookup and manipulation
=====================
All variable and data passed into h2o are stored in the context object for variable name lookup.. 

1. Resolve a variable, number, string, boolean in the given context
context->resolve('person.name')

2. Setting variable
context->set('person', array('name'=>'peter', 'age'=>18))

entries.html

{% load 'load_entries' %} 
{% load_entries name:'entries', immediate:true, format:'native', days_ago:"99999", paginate:true, max_per_page: 15 %}

<ul>
{% for entry in entries %}
  <li>{{ entry.name | links_to entry.url }}</li>
{% endfor %}
</ul>

load_entries.php

<?php
  h2o::addTag('load_entries');
  class Load_entries_tag extends H2o_Node {
      var $options;
      function __construct($argstring, $parser, $pos=0) {
           $args = H2o_Parser::parseArguments($argstring);
      }

      function render($context, $stream) {
          // Do your SQL query 
          $entries = Entry::getInstance()->findAll($this->options);
          $context->set('entries', $entries);
      }
  }

?>