Domain Specific Languages

Chapter 43. Parse Tree Manipulation

Capture the parse tree of a code fragment to manipulate it with DSL processing code.

When you write code in a closure, that code is available to be executed at some future time. Parse Tree Manipulation allows you to not only execute the code but also examine and modify its parse tree.

43.1 How It Works

In order to use Parse Tree Manipulation, you need a programming environment that supports taking a code fragment and turning it into a parse tree that you can work with. This is a relatively rare programming language feature—rare both in that few languages support it and in that, even when it is supported, ...