An infinite loop was corrected.

Package.php

@@ -0,0 +1,105 @@
+<?php
+
+require_once __DIR__ . '/helpers/yaml.php';
+require_once __DIR__ . '/Source.php';
+
+class Package
+{
+	protected $sources = array();
+
+	public function __construct($package_path = '')
+	{
+		if ($package_path){
+			$this->path = $this->resolve_path($package_path);
+			$this->root_dir = dirname($this->path);
+			$this->parse($this->path);
+		}
+	}
+
+	public function __toString()
+	{
+		return $this->get_name();
+	}
+
+	static function decode($path){
+		return preg_match('/\.json$/', $path) ? json_decode(file_get_contents($path), true) : YAML::decode_file($path);
+	}
+
+	static function glob($path, $pattern = '*', $flags = 0, $depth = 0){
+		$matches = array();
+		$folders = array(rtrim($path, DIRECTORY_SEPARATOR));
+
+		while ($folder = array_shift($folders)){
+			$matches = array_merge($matches, glob($folder.DIRECTORY_SEPARATOR.$pattern, $flags));
+
+			if (!$depth) continue;
+
+			$moreFolders = glob($folder.DIRECTORY_SEPARATOR.'*', GLOB_ONLYDIR);
+			$depth = ($depth < -1) ? -1: $depth + count($moreFolders) - 2;
+			$folders = array_merge($folders, $moreFolders);
+		}
+		return $matches;
+	}
+
+	public function add_source($source_path = '')
+	{
+		if (!is_a($source_path, 'Source')) $source_path = new Source($this->get_name(), $source_path);
+		$this->sources[] = $source_path;
+	}
+
+	public function get_name()
+	{
+		return $this->name;
+	}
+
+	public function get_path()
+	{
+		return $this->path;
+	}
+
+	public function get_sources()
+	{
+		return $this->sources;
+	}
+
+	public function parse($package_path)
+	{
+		$package = self::decode($package_path);
+
+		foreach ($package as $key => $value){
+			$method = 'parse_' . strtolower($key);
+			if (is_callable(array($this, $method))) $this->$method($value);
+		}
+	}
+
+	public function parse_name($name)
+	{
+		$this->set_name($name);
+	}
+
+	public function parse_sources($sources)
+	{
+		# todo(ibolmo): 5, should be a class option.
+		if (is_string($sources)) $sources = self::glob($this->path, $sources, 0, 5);
+		foreach ($sources as $source) $this->add_source($this->root_dir . '/' . $source);
+	}
+
+	public function set_name($name)
+	{
+		$this->name = $name;
+		return $this;
+	}
+
+	public function resolve_path($path){
+		if (!is_dir($path) && file_exists($path)) return $path;
+
+		$pathinfo = pathinfo($path);
+		$path = $pathinfo['dirname'] . '/' . $pathinfo['basename'] . '/';
+
+		if (file_exists($path . 'package.yml')) return $path . 'package.yml';
+		if (file_exists($path . 'package.yaml')) return $path . 'package.yaml';
+		if (file_exists($path . 'package.json')) return $path . 'package.json';
+
+		throw new Exception("package.(ya?ml|json) not found in $path.");
+	}
+}

Packager.php

@@ -0,0 +1,174 @@
+<?php
+
+# todo(ibolmo): packages with the same name cause an endless loop
+
+require_once __DIR__ . '/Package.php';
+
+class Packager {
+
+	static $instance;
+
+	protected $sources = array();
+	protected $generators = array();
+	protected $keys = array();
+
+	public function __construct($package_paths = '')
+	{
+		$this->configure();
+		if ($package_paths) foreach ((array) $package_paths as $package) $this->add_package($package);
+	}
+
+	static function get_instance()
+	{
+		if (!self::$instance) self::$instance = new Packager();
+		return self::$instance;
+	}
+
+	static function strip_blocks($code, $blocks)
+	{
+		foreach ((array) $blocks as $block){
+			$code = preg_replace_callback("%(/[/*])\s*<$block>(.*?)</$block>(?:\s*\*/)?%s", function($matches){
+				return (strpos($matches[2], ($matches[1] == "//") ? "\n" : "*/") === false) ? $matches[2] : "";
+			}, $code);
+		}
+		return $code;
+	}
+
+	public function add_component(Source $source, $component)
+	{
+		$index = $this->get_source_index($source);
+		if ($index < 0) $index = $this->add_source($source);
+
+		foreach ($this->generators as $name => $callback){
+			$key = call_user_func($callback, $source, $component);
+			$this->set_key($key, $index, $name);
+		}
+
+		return $index;
+	}
+
+	public function add_generator($name, $callback)
+	{
+		$this->generators[$name] = $callback;
+	}
+
+	public function add_package($package)
+	{
+		if (!is_a($package, 'Package')) $package = new Package($package);
+		$this->packages[$package->get_name()] = $package;
+	}
+
+	public function add_source(Source $source)
+	{
+		$index = array_push($this->sources, $source) - 1;
+		return $this->keys[$source->get_name()] = $index;
+	}
+
+ 	public function build(Source $source)
+	{	
+		$build = array_map(function($source){
+			return $source->get_code();	
+		}, $this->get_required_for_source($source));
+		$build[] = $source->get_code();
+		return implode('', $build);
+	}
+
+	public function configure()
+	{
+		$this->add_generator('component name', function(Source $source, $component){
+			return $component;
+		});
+
+		$this->add_generator('package and source name', function(Source $source, $component){
+			return sprintf('%s/%s', $source->get_package_name(), $source->get_name());
+		});
+
+		$this->add_generator('package and component name', function(Source $source, $component){
+			return sprintf('%s/%s', $source->get_package_name(), $component);
+		});
+	}
+
+	public function get_packages()
+	{
+		return $this->packages;
+	}
+
+	public function get_source_by_name($name)
+	{
+		$index = $this->get_source_index($name);
+		if ($index > -1) return $this->sources[$index];
+
+		$this->warn("Could not find source '$name'.");
+		return null;
+	}
+
+	public function get_source_index($key)
+	{
+		if ($key instanceof Source) $key = $key->get_name();
+		return isset($this->keys[$key]) ? $this->keys[$key] : -1;
+	}
+
+	public function get_sources()
+	{
+		return $this->sources;
+	}
+
+	public function get_required_for_source(Source $source, &$required = null)
+	{	
+		$return = false;
+		if (!$required){
+			$return = true;
+			$required = array();
+		}
+
+		foreach ($source->get_requires() as $require){
+			if (!($require instanceof Source)) $require = $this->get_source_by_name($require);
+			if (!$require) continue;
+			if ($require->has_requires()) $this->get_required_for_source($require, $required);
+		}
+		foreach ($source->get_requires() as $require){
+			if (!($require instanceof Source)) $require = $this->get_source_by_name($require);
+			if (!$require) continue;
+			if (!in_array($require, $required)) $required[] = $require;
+		}
+
+		if ($return) return $required;
+	}
+
+	public function remove_component(Source $source, $component)
+	{
+		foreach ($this->generators as $name => $callback){
+			$key = call_user_func($callback, $source, $component);
+			unset($this->keys[$key]);
+		}
+	}
+
+	public function remove_package($package_name)
+	{
+		if ($package_name instanceof Package) $package_name = $package_name->get_name();
+		if (!isset($this->packages[$package_name])) return false;
+		foreach($this->packages[$package_name]->get_sources() as $source) $this->remove_source($source);
+		unset($this->packages[$package_name]);
+		return true;
+	}
+
+	public function remove_source(Source $source)
+	{
+		$name = $source->get_name();
+		$index = $this->keys[$name];
+		foreach ($source->get_provides() as $component) $this->remove_component($source, $component);
+		unset($this->keys[$name], $this->sources[$index]);
+	}
+
+	protected function set_key($key, $index, $generator_name)
+	{
+		if (isset($this->keys[$key])) $this->warn("Generator '$generator_name' set component key '$key'.");
+		$this->keys[$key] = $index;
+	}
+
+	protected function warn($message)
+	{
+		# todo(ibolmo): log mixin
+	}
+
+}