/*
* Waxeye Parser Generator
* www.waxeye.org
* Copyright (C) 2008-2010 Orlando Hill
* Licensed under the MIT license. See 'LICENSE' for details.
*/
package org.waxeye.ast;
import java.util.List;
import org.waxeye.ast.print.ArrowPrinter;
/**
* A class to represent an abstract syntax tree.
*
* @param <E> The node types for the AST.
*
* @author Orlando Hill
*/
public final class AST <E extends Enum<?>> implements IAST<E>
{
/** The type of AST node. */
private final E type;
/** The children of the AST. */
private final List<IAST<E>> children;
/** The position of the AST. */
private final Position position;
/**
* Creates a new AST.
*
* @param type The type of the AST.
*
* @param children The children of the AST.
*
* @param position The position of the AST.
*/
public AST(final E type, final List<IAST<E>> children,
final Position position)
{
this.type = type;
this.children = children;
this.position = position;
assert invariants();
}
/**
* Checks the invariants of the object.
*
* @return <code>true</code>.
*/
private boolean invariants()
{
assert type != null;
assert children != null;
return true;
}
/** {@inheritDoc} */
public boolean equals(final Object object)
{
if (this == object)
{
return true;
}
if (object != null && object.getClass() == this.getClass())
{
final AST<E> p = (AST<E>) object;
if (type.equals(p.type) && children.equals(p.children))
{
return true;
}
}
return false;
}
/** {@inheritDoc} */
public int hashCode()
{
final int start = 17;
final int mult = 37;
int result = start * type.hashCode();
for (IAST<E> t : children)
{
result = mult * result + t.hashCode();
}
return Math.abs(result);
}
/** {@inheritDoc} */
public List<IAST<E>> getChildren()
{
return children;
}
/** {@inheritDoc} */
public Position getPosition()
{
return position;
}
/** {@inheritDoc} */
public E getType()
{
return type;
}
/** {@inheritDoc} */
public void acceptASTVisitor(final IASTVisitor visitor)
{
visitor.visitAST(this);
}
/** {@inheritDoc} */
public final String childrenAsString()
{
final StringBuilder buf = new StringBuilder();
for (IAST<E> c : children) {
buf.append(((IChar) c).getValue());
}
return buf.toString();
}
/** {@inheritDoc} */
public String toString()
{
return new ArrowPrinter(this).toString();
}
}