Incorrect documentation for caching

[Elendev]

The last example of the Expression language caching section (https://github.com/symfony/symfony-docs/blob/2.6/components/expression_language/caching.rst) doesn't work :

$expression = new SerializedParsedExpression(
        serialize($language->parse('1 + 4', array()))
    );

The SerializedParsedExpression constructor requires a $nodes parameters.
I'm not really sure on how to do it the right way.

[stof]

The first argument should be the expression itself, which is missing here. I sent a PR fixing it

[Elendev]

So, if I understand correctly : if I want to optimize an expression evaluation by serializing it, for example in database, I have to keep both the serialized parsed expression and the expression to be able to use it with SerializedParsedExpression ?

[stof]

@Elendev yes, because the expression object must be able to give the original expression when being casted as string.

[Elendev]

@stof ok I understand, thank you for the explanation