The Workflow

Both ``evaluate`` and ``compile`` need to do some things before each can

provide the return values. For ``evaluate``, this overhead is even bigger.

Both:method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::evaluate`

and ``compile()`` need to do some things before each can provide the return

values. For ``evaluate()``, this overhead is even bigger.

Both methods need to tokenize and parse the expression. This is done by the

Both methods need to tokenize and parse the expression. This is done by the

:method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::parse`

method. It returns a:class:`Symfony\\Component\\ExpressionLanguage\\ParsedExpression`.

Now, the ``compile`` method just returns the string conversion of this object.

The ``evaluate`` method needs to loop through the "nodes" (pieces of an

Now, the ``compile()`` method just returns the string conversion of this object.

The ``evaluate()`` method needs to loop through the "nodes" (pieces of an

expression saved in the ``ParsedExpression``) and evaluate them on the fly.

To save time, the ``ExpressionLanguage`` caches the ``ParsedExpression`` so

..note::

The `DoctrineBridge`_has aParserCache implementation using the

The `DoctrineBridge`_provides aParser Cache implementation using the

`doctrine cache library`_, which gives you caching for all sorts of cache

strategies, like Apc, Filesystem andApc.

strategies, like Apc, Filesystem andMemcached.

Using Parsed and Serialized Expressions

Both ``evaluate`` and ``compile`` can handle ``ParsedExpression`` and

Both ``evaluate()`` and ``compile()`` can handle ``ParsedExpression`` and

``SerializedParsedExpression``::