polyglot.visit
Class FlattenVisitor
java.lang.Object
polyglot.visit.NodeVisitor
polyglot.visit.FlattenVisitor
- All Implemented Interfaces:
- java.lang.Cloneable, Copy
public class FlattenVisitor
- extends NodeVisitor
The FlattenVisitor flattens the AST,
Method Summary |
NodeVisitor |
enter(Node parent,
Node n)
When entering a BlockStatement, place a new StatementList
onto the stack |
Node |
leave(Node old,
Node n,
NodeVisitor v)
Flatten complex expressions within the AST |
protected static java.lang.String |
newID()
|
Node |
override(Node parent,
Node n)
Given a tree rooted at n , the visitor has the option of
overriding all traversal of the children of n . |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
ts
protected TypeSystem ts
nf
protected NodeFactory nf
stack
protected java.util.LinkedList stack
noFlatten
protected java.util.Set noFlatten
neverFlatten
protected java.util.Set neverFlatten
FlattenVisitor
public FlattenVisitor(TypeSystem ts,
NodeFactory nf)
override
public Node override(Node parent,
Node n)
- Description copied from class:
NodeVisitor
- Given a tree rooted at
n
, the visitor has the option of
overriding all traversal of the children of n
. If no
changes were made to n
and the visitor wishes to prevent
further traversal of the tree, then it should return n
. If
changes were made to the subtree, then the visitor should return a
copy of n
with appropriate changes. Finally, if the
visitor does not wish to override traversal of the subtree rooted at
n
, then it should return null
.
The default implementation of this method is to call
override(n)
, as most subclasses do not need to know
the parent of the node n
.
- Overrides:
override
in class NodeVisitor
- Parameters:
parent
- The parent of n
,
null
if n
has no parent.n
- The root of the subtree to be traversed.
- Returns:
- A node if normal traversal is to stop,
null
if it
is to continue.
newID
protected static java.lang.String newID()
enter
public NodeVisitor enter(Node parent,
Node n)
- When entering a BlockStatement, place a new StatementList
onto the stack
- Overrides:
enter
in class NodeVisitor
- Parameters:
parent
- The parent of n
, null
if n
has no parent.n
- The root of the subtree to be traversed.
- Returns:
- The
NodeVisitor
which should be used to visit the
children of n
.
leave
public Node leave(Node old,
Node n,
NodeVisitor v)
- Flatten complex expressions within the AST
- Overrides:
leave
in class NodeVisitor
- Parameters:
old
- The original state of root of the current subtree.n
- The current state of the root of the current subtree.v
- The NodeVisitor
object used to visit the children.
- Returns:
- The final result of the traversal of the tree rooted at
n
.