Class BaseTreeAdaptor

Return a nil node (an empty but non-null node) that can hold a list of element as the children. If you want a flat tree (a list) use "t=adaptor.nil(); t.addChild(x); t.addChild(y);"

Overrides: TreeAdaptor.nil

(inherited documentation)

create tree node that holds the start and stop tokens associated with an error.

If you specify your own kind of tree nodes, you will likely have to override this method. CommonTree returns Token.INVALID_TOKEN_TYPE if no token payload but you might have to set token type for diff node type.

You don't have to subclass CommonErrorNode; you will likely need to subclass your own tree node class to avoid class cast exception.

Overrides: TreeAdaptor.errorNode

Is tree considered a nil node used to make lists of child nodes?

Overrides: TreeAdaptor.isNil

(inherited documentation)

This is generic in the sense that it will work with any kind of tree (not just Tree interface). It invokes the adaptor routines not the tree node routines to do the construction.

Overrides: TreeAdaptor.dupTree

Add a child to the tree t. If child is a flat tree (a list), make all in list children of t. Warning: if t has no children, but child does and child isNil then you can decide it is ok to move children to t via t.children = child.children; i.e., without copying the array. Just make sure that this is consistent with have the user will build ASTs.

Overrides: TreeAdaptor.addChild

If oldRoot is a nil root, just copy or move the children to newRoot.
If not a nil root, make oldRoot a child of newRoot.

  old=^(nil a b c), new=r yields ^(r a b c)
  old=^(a b c), new=r yields ^(r ^(a b c))

If newRoot is a nil-rooted single child tree, use the single
child as the new root node.

  old=^(nil a b c), new=^(nil r) yields ^(r a b c)
  old=^(a b c), new=^(nil r) yields ^(r ^(a b c))

If oldRoot was null, it's ok, just return newRoot (even if isNil).

  old=null, new=r yields r
  old=null, new=^(nil r) yields ^(nil r)

Return newRoot.  Throw an exception if newRoot is not a
simple node or nil root with a single child node--it must be a root
node.  If newRoot is ^(nil x) return x as newRoot.

Be advised that it's ok for newRoot to point at oldRoot's
children; i.e., you don't have to copy the list.  We are
constructing these nodes so we should have this control for
efficiency.

Overrides: TreeAdaptor.becomeRoot

Transform ^(nil x) to x and nil to null

Overrides: TreeAdaptor.rulePostProcessing

Create a new node derived from a token, with a new token type and (optionally) new text.

This is invoked from an imaginary node ref on right side of a rewrite rule as IMAG[$tokenLabel] or IMAG[$tokenLabel "IMAG"].

This should invoke createToken(Token).

Overrides: TreeAdaptor.createFromToken

(inherited documentation)

Create a new node derived from a token, with a new token type.

This is invoked from an imaginary node ref on right side of a rewrite rule as IMAG["IMAG"].

This should invoke createToken(int,String).

Overrides: TreeAdaptor.createFromType

(inherited documentation)

For tree parsing, I need to know the token type of a node

Overrides: TreeAdaptor.getType

(inherited documentation)

Node constructors can set the type of a node

Overrides: TreeAdaptor.setType

(inherited documentation)

Overrides: TreeAdaptor.getText

Node constructors can set the text of a node

Overrides: TreeAdaptor.setText

(inherited documentation)

Get a child 0..n-1 node

Overrides: TreeAdaptor.getChild

(inherited documentation)

Set ith child (0..n-1) to t; t must be non-null and non-nil node

Overrides: TreeAdaptor.setChild

(inherited documentation)

Remove ith child and shift children down from right.

Overrides: TreeAdaptor.deleteChild

(inherited documentation)

How many children? If 0, then this is a leaf node

Overrides: TreeAdaptor.getChildCount

(inherited documentation)

For identifying trees.

How to identify nodes so we can say "add node to a prior node"? Even becomeRoot is an issue. Use System.identityHashCode(node) usually.

Overrides: TreeAdaptor.getUniqueID

(inherited documentation)

Tell me how to create a token for use with imaginary token nodes. For example, there is probably no input symbol associated with imaginary token DECL, but you need to create it as a payload or whatever for the DECL node as in ^(DECL type ID).

If you care what the token payload objects' type is, you should override this method and any other createToken variant.