package org.jruby.ast.visitor;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.jruby.ast.ClassNode;
import org.jruby.ast.InstAsgnNode;
import org.jruby.ast.InstVarNode;
import org.jruby.ast.ModuleNode;
import org.jruby.ast.Node;
import org.jruby.ast.PostExeNode;
import org.jruby.ast.PreExeNode;
/**
* Visitor to search AST nodes for instance variables. Certain nodes are
* ignored during walking since they always create a new context with a new
* self.
*
* Example usage:
*
* <code>
* Node node = getNodeFromSomewhere();
* InstanceVariableFinder finder = new InstanceVariableFinder();
* node.accept(finder);
* System.out.println("found: " + finder.getFoundVariables);
* </code>
*/
public class InstanceVariableFinder extends AbstractNodeVisitor<Void> {
@Override
protected Void defaultVisit(Node iVisited) {
visitChildren(iVisited);
return null;
}
/** The set of instance variables found during walking. */
private final Set<String> foundVariables = new HashSet<String>();
/**
* Walk a node and its children looking for instance variables using a new
* InstanceVariableFinder. Return an array of the variable names found.
*
* @param node the node to walk
* @return an array of instance variable names found
*/
public static Set<String> findVariables(Node node) {
InstanceVariableFinder ivf = new InstanceVariableFinder();
node.accept(ivf);
return ivf.getFoundVariables();
}
/**
* Return the Set of all instance variables found during walking.
*
* @return a Set of all instance variable names found
*/
public Set<String> getFoundVariables() {
return foundVariables;
}
/**
* ClassNode creates a new scope and self, so do not search for ivars.
*
* @return null
*/
@Override
public Void visitClassNode(ClassNode iVisited) {
return null;
}
/**
* Add the name of the instance variable being assigned to our set of
* instance variable names and continue to walk child nodes.
*
* @return null
*/
@Override
public Void visitInstAsgnNode(InstAsgnNode iVisited) {
foundVariables.add(iVisited.getName());
List<Node> nodes = iVisited.childNodes();
for (int i = 0; i < nodes.size(); i++) {
Node node = nodes.get(i);
node.accept(this);
}
return null;
}
/**
* Add the name of the instance variable being retrieved to our set of
* instance variable names and continue to walk child nodes.
*
* @return null
*/
@Override
public Void visitInstVarNode(InstVarNode iVisited) {
foundVariables.add(iVisited.getName());
List<Node> nodes = iVisited.childNodes();
for (int i = 0; i < nodes.size(); i++) {
Node node = nodes.get(i);
}
return null;
}
/**
* ModuleNode creates a new scope and self, so do not search for ivars.
*
* @return null
*/
@Override
public Void visitModuleNode(ModuleNode iVisited) {
return null;
}
/**
* PreExeNode can't appear in methods, so do not search for ivars.
*
* @return null
*/
@Override
public Void visitPreExeNode(PreExeNode iVisited) {
return null;
}
/**
* PostExeNode can't appear in methods, so do not search for ivars.
*
* @return null
*/
@Override
public Void visitPostExeNode(PostExeNode iVisited) {
return null;
}
}