Module rowan::ast

Working with abstract syntax trees.

In rowan, syntax trees are transient objects. That means that we create trees when we need them, and tear them down to save memory. In this architecture, hanging on to a particular syntax node for a long time is ill-advisable, as that keeps the whole tree resident.

Instead, we provide a SyntaxNodePtr type, which stores information about the location of a particular syntax node in a tree. It’s a small type which can be cheaply stored, and which can be resolved to a real SyntaxNode when necessary.

We also provide an AstNode trait for typed AST wrapper APIs over rowan nodes.

Modules

• support

Structs

• AstChildren
• AstPtr
  Like SyntaxNodePtr, but remembers the type of node.
• SyntaxNodePtr
  A “pointer” to a SyntaxNode, via location in the source code.

Traits

• AstNode
  The main trait to go from untyped SyntaxNode to a typed AST. The conversion itself has zero runtime cost: AST and syntax nodes have exactly the same representation: a pointer to the tree root and a pointer to the node itself.