OoasTools

/**

  *

  *                      OOAS Compiler

  *

  *       Copyright 2015, AIT Austrian Institute of Technology.

  * This code is based on the C# Version of the OOAS Compiler, which is

  * copyright 2015 by the Institute of Software Technology, Graz University

  * of Technology with portions copyright by the AIT Austrian Institute of

  * Technology. All rights reserved.

  *

  * SEE THE "LICENSE" FILE FOR THE TERMS UNDER WHICH THIS FILE IS PROVIDED.

  *

  * If you modify the file please update the list of contributors below to in-

  * clude your name. Please also stick to the coding convention of using TABs

  * to do the basic (block-level) indentation and spaces for anything after

  * that. (Enable the display of special chars and it should be pretty obvious

  * what this means.) Also, remove all trailing whitespace.

  *

  * Contributors:

  *               Willibald Krenn (AIT)

  *               Stephan Zimmerer (AIT)

  *               Markus Demetz (AIT)

  *               Christoph Czurda (AIT)

  *

  */

package org.momut.ooas.visitors.optimisation;

import org.momut.ooas.utils.exceptions.InternalCompilerException;

/// <summary>

/// removes trivial prioritized compositions.

/// </summary>

public final class OoaRemoveTrivialPrioritizedCompositionVisitor extends OoaCompleteAstTraversalVisitor

{

	/// <summary>

	/// replaces the prioBlock by its child (most likely a parBlock)

	/// </summary>

	private IAst ConvertPrioBlock(PrioBlock prioBlock, IAst parent)

	{

		if (prioBlock.statements().size() <= 1 && prioBlock.isSimpleBlock())

		{

			final Block newBlock = (Block)prioBlock.statements().peekFirst();

			newBlock.SetParentScope(prioBlock.GetParentScope());

			switch (parent.nodeType())

			{

			case type:

				switch (((UlyssesType)parent).kind())

				{

				case OoActionSystemType:

					final OoActionSystemType atype = (OoActionSystemType)parent;

					final Block ablock = atype.doOdBlock();

					assert(ablock == prioBlock); // ref equ.

					atype.SetDoOdBlock(newBlock);

					break;

				default:

					throw new NotImplementedException();

				}

				break;

			case statement:

				switch (((Statement)parent).kind())

				{

				case SeqBlock:

					final SeqBlock aseqblock = (SeqBlock)parent;

					final int idx = aseqblock.statements().indexOf(prioBlock);

					if (idx == -1)

						throw new OoasCompilerRuntimeException(); // must not happen?!

					aseqblock.statements().set(idx, newBlock);

//					LinkedListNode<Statement> toChange = aseqblock.statements.Find(prioBlock);

//					toChange.Value = newBlock;

					break;

				case GuardedCommand:

					final GuardedCommand gc = (GuardedCommand)parent;

					assert(gc.body() == prioBlock); // ref equ.

					gc.SetBody(newBlock);

					break;

				default:

					throw new NotImplementedException();

				}

				break;

			case identifier:

				switch (((Identifier)parent).kind())

				{

				case NamedActionIdentifier:

					final NamedActionIdentifier action = (NamedActionIdentifier)parent;

					if (action.body() != prioBlock) // ref equ.

						throw new InternalCompilerException("Internal Error: Cannot replace action body.");

					action.SetBody(newBlock);

					break;

				case MethodIdentifier:

					final MethodIdentifier method = (MethodIdentifier)parent;

					assert(method.body() == prioBlock); // ref equ.

					method.SetBody(newBlock);

					break;

				default:

					throw new NotImplementedException();

				}

				break;

			default:

				throw new NotImplementedException();

			}

			m_changes = true;

			return newBlock;

		}

		else

			return prioBlock;

	}

	@Override

	protected void VisitAstElement(IAst element, IAst parent)

	{

		if ((element.nodeType() == AstNodeTypeEnum.statement) &&

				(((Statement)element).kind() == StatementKind.PrioBlock) &&

				// we're only interested in actionblock and actionbody composition, not in type composition

				!(parent.nodeType() == AstNodeTypeEnum.identifier && ((Identifier)parent).kind() == IdentifierKind.List))

		{

			final IAst newchild = ConvertPrioBlock((PrioBlock)element, parent);

			super.VisitAstElement(newchild, parent);

		}

		else

			super.VisitAstElement(element, parent);

	}

	@Override

	public void visit(MainModule mainModule)

	{

		// get rid of any top-level spurious block

		if (mainModule.systemDescription() != null)

			while (mainModule.systemDescription().identifiers().size() == 1

			       && mainModule.systemDescription().identifiers().peekFirst().kind() == IdentifierKind.List)

			{

				mainModule.SetSystemDescription((IdentifierList)mainModule.systemDescription().identifiers().peekFirst());

			}

		super.visit(mainModule);

	}

	private boolean m_changes = false;

	public OoaRemoveTrivialPrioritizedCompositionVisitor(ParserState aState)

	{

		super (aState);

	}

	public boolean changedAst() {

		return m_changes;

	}

}