public abstract Class AbstractParseTreeVisitor<T>

Aggregates the results of visiting multiple children of a node. After either all children are visited or shouldVisitNextChild returns false, the aggregate value is returned as the result of visitChildren.

The default implementation returns nextResult, meaning visitChildren will return the result of the last child visited (or return the initial value if the node has no children).

Parameters

aggregate:T

The previous aggregate value. In the default implementation, the aggregate value is initialized to defaultResult, which is passed as the aggregate argument to this method after the first child node is visited.

nextResult:T

The result of the immediately preceeding call to visit a child node.

Returns:T

The updated aggregate result.

Gets the default value returned by visitor methods. This value is returned by the default implementations of visitTerminal, visitErrorNode. The default implementation of visitChildren initializes its aggregate result to this value.

The base implementation returns null.

Returns:T

The default value returned by visitor methods.

This method is called after visiting each child in visitChildren. This method is first called before the first child is visited; at that point currentResult will be the initial value (in the default implementation, the initial value is returned by a call to defaultResult. This method is not called after the last child is visited.

The default implementation always returns true, indicating that visitChildren should only return after all children are visited. One reason to override this method is to provide a "short circuit" evaluation option for situations where the result of visiting a single child has the potential to determine the result of the visit operation as a whole.

Parameters

node:RuleNode

The RuleNode whose children are currently being visited.

currentResult:T

The current aggregate result of the children visited to the current point.

Returns:boolean

true to continue visiting children. Otherwise return false to stop visiting children and immediately return the current aggregate result from visitChildren.