Fragments

When the parser breaks up the Text to find and handle expressions, all the pieces are known as fragments. A fragment can either be a TextFragment or an ExpressionFragment.

ExpressionFragment

When you work with an ExpressionFragment it's important to understand its methods and their rather small, but important, discrepancies.

Let's imagine an expression p:name(). When you handle an ExpressionFragment this is its foundation (or signature). You retrieve the raw expression with ExpressionFragment::foundation method. With ExpressionFragment::rebase you can change the expression itself. If you're interested in a practical usecase you can explore the source code of Text::transform - which is also described further in how to convert expression patterns.

The probably more interesting part is get and set which works with its output. The result of the expression.

For example, if you want to perform an uppercase operation on all printed variables, you can do this:

$text->on('p')->do(function($fragment) {
    return strtoupper($fragment->get());
});

TextFragment

The TextFragment is built with the same logic at hand, but due to its nature there's no difference between working with output or foundation.