1 files changed, 149 insertions, 0 deletions
diff --git a/Mustache/Context.php b/Mustache/Context.php
new file mode 100644
index 0000000..7bc7571
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+++ b/Mustache/Context.php
@@ -0,0 +1,149 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Mustache Template rendering Context.
+ */
+class Mustache_Context
+{
+    private $stack = array();
+
+    /**
+     * Mustache rendering Context constructor.
+     *
+     * @param mixed $context Default rendering context (default: null)
+     */
+    public function __construct($context = null)
+    {
+        if ($context !== null) {
+            $this->stack = array($context);
+        }
+    }
+
+    /**
+     * Push a new Context frame onto the stack.
+     *
+     * @param mixed $value Object or array to use for context
+     */
+    public function push($value)
+    {
+        array_push($this->stack, $value);
+    }
+
+    /**
+     * Pop the last Context frame from the stack.
+     *
+     * @return mixed Last Context frame (object or array)
+     */
+    public function pop()
+    {
+        return array_pop($this->stack);
+    }
+
+    /**
+     * Get the last Context frame.
+     *
+     * @return mixed Last Context frame (object or array)
+     */
+    public function last()
+    {
+        return end($this->stack);
+    }
+
+    /**
+     * Find a variable in the Context stack.
+     *
+     * Starting with the last Context frame (the context of the innermost section), and working back to the top-level
+     * rendering context, look for a variable with the given name:
+     *
+     *  * If the Context frame is an associative array which contains the key $id, returns the value of that element.
+     *  * If the Context frame is an object, this will check first for a public method, then a public property named
+     *    $id. Failing both of these, it will try `__isset` and `__get` magic methods.
+     *  * If a value named $id is not found in any Context frame, returns an empty string.
+     *
+     * @param string $id Variable name
+     *
+     * @return mixed Variable value, or '' if not found
+     */
+    public function find($id)
+    {
+        return $this->findVariableInStack($id, $this->stack);
+    }
+
+    /**
+     * Find a 'dot notation' variable in the Context stack.
+     *
+     * Note that dot notation traversal bubbles through scope differently than the regular find method. After finding
+     * the initial chunk of the dotted name, each subsequent chunk is searched for only within the value of the previous
+     * result. For example, given the following context stack:
+     *
+     *     $data = array(
+     *         'name' => 'Fred',
+     *         'child' => array(
+     *             'name' => 'Bob'
+     *         ),
+     *     );
+     *
+     * ... and the Mustache following template:
+     *
+     *     {{ child.name }}
+     *
+     * ... the `name` value is only searched for within the `child` value of the global Context, not within parent
+     * Context frames.
+     *
+     * @param string $id Dotted variable selector
+     *
+     * @return mixed Variable value, or '' if not found
+     */
+    public function findDot($id)
+    {
+        $chunks = explode('.', $id);
+        $first  = array_shift($chunks);
+        $value  = $this->findVariableInStack($first, $this->stack);
+
+        foreach ($chunks as $chunk) {
+            if ($value === '') {
+                return $value;
+            }
+
+            $value = $this->findVariableInStack($chunk, array($value));
+        }
+
+        return $value;
+    }
+
+    /**
+     * Helper function to find a variable in the Context stack.
+     *
+     * @see Mustache_Context::find
+     *
+     * @param string $id    Variable name
+     * @param array  $stack Context stack
+     *
+     * @return mixed Variable value, or '' if not found
+     */
+    private function findVariableInStack($id, array $stack)
+    {
+        for ($i = count($stack) - 1; $i >= 0; $i--) {
+            if (is_object($stack[$i])) {
+                if (method_exists($stack[$i], $id)) {
+                    return $stack[$i]->$id();
+                } elseif (isset($stack[$i]->$id)) {
+                    return $stack[$i]->$id;
+                }
+            } elseif (is_array($stack[$i]) && array_key_exists($id, $stack[$i])) {
+                return $stack[$i][$id];
+            }
+        }
+
+        return '';
+    }
+}