This module defines types for a Ceylon Abstract Syntax Tree (AST),
a hierarchical and immutable data structure that represents a Ceylon program.
# Obtaining an AST
There are two major ways to obtain an AST:
## Create it yourself
You can of course construct the AST yourself.
To reduce the amount of boilerplate code necessary, we *strongly* recommend
using the [[`ceylon.ast.create` module|module ceylon.ast.create]];
this will, for example, allow you to write
baseExpression("null")
...