====== Source Resolver ======

You can create fake filesystems for PHPTAL templates. This lets you load templates //and macros// from any source, e.g. a database.

===== Simplest way =====

If you don't use macros, you don't need ''SourceResolver'':

     $phptal->setSource(load_source_from_anywhere());  // No source resolver necessary

===== Implementing custom source =====

However, if you'd like to avoid fetching template source on every request (explained later), or would like to use macros that load additional templates, implement your own ''SourceResolver'':

     class MySourceResolver implements PHPTAL_SourceResolver
     {
         function resolve($path)
         {
             if (looks_like_my_path($path)) {
                 $source = load_template_from($path);
                 return new PHPTAL_StringSource($source);
             }
         }
     }

:!: (in PHPTAL older than 1.2.2 you need ''new PHPTAL_StringSource($source, md5($source))'')

The ''resolve'' function should return instance of ''PHPTAL_Source'' (if it supports the path) or ''NULL''. You can either use ''PHPTAL_StringSource'' class, or implement your own.

     $phptal->addSourceResolver(new MySourceResolver());

PHPTAL will call ''resolve()'' method whenever it needs to load a template set via ''setTemplate()'' or ''metal:use-macro''. ()

==== Lazy loading of templates ====

''PHPTAL_SourceResolver::resolve()'' method could return object that doesn't load template immediately, and instead just returns information needed to load compiled template from cache:

    class MyLazyTemplate extends PHPTAL_Source
    {
        function getRealPath()
        {
            return 'fake:/my/template'; // doesn't have to be on disk
        }
        
        function getLastModifiedTime()
        {
            return mktime(0,0,0, 7,7,2010); // unix timestamp
        }
        
        function getData()
        {
            return load_the_template();
        }
    }

PHPTAL will call ''getData()'' only when ''getRealPath()'' or ''getLastModifiedTime()'' return different values.()