Block.java

package de.fuberlin.projecta.analysis.ast;

import de.fuberlin.commons.lexer.TokenType;
import de.fuberlin.commons.parser.ISyntaxTree;
import de.fuberlin.projecta.analysis.SymbolTableStack;

public class Block extends Statement {
	/**
	 * Used for naming conventions in declarations
	 */
	private int memoryCounter;

	@Override
	public void buildSymbolTable(SymbolTableStack stack) {
		stack.push();
		for (int i = 0; i < this.getChildrenCount(); i++) {
			((AbstractSyntaxTree) (this.getChild(i))).buildSymbolTable(stack);
		}
		table = stack.pop();
	}

	// using super implementation for genCode

	public int getNewVar() {
		return ++memoryCounter;
	}

	public int getCurrentRegister() {
		return memoryCounter;
	}

	protected boolean hasReturnStatement() {
		if (this.getChildrenCount() > 0) {
			ISyntaxTree last = this.getChild(this.getChildrenCount() - 1);
			if (last instanceof Block) {
				return ((Block) last).hasReturnStatement();
			} else {
				return last instanceof Return;
			}
		}
		return false;
	}

	protected boolean couldAmmendReturnStatement() {
		// Blocks don't exist if they are empty!
		ISyntaxTree lastStatement = this.getChild(this.getChildrenCount() - 1);
		if (lastStatement instanceof Block) {
			return ((Block) lastStatement).couldAmmendReturnStatement();
		} else if (lastStatement instanceof Do) {
			return ((Do) lastStatement).couldAmmendReturnStatement();
		} else if (lastStatement instanceof IfElse) {
			return ((IfElse) lastStatement).couldAmmendReturnStatement();
		} else if (lastStatement instanceof BinaryOp) {
			BinaryOp binOp = (BinaryOp) lastStatement;
			if (binOp.getOp() == TokenType.OP_ASSIGN) {
				// first child has to be an identifier. This is checked
				// beforehand!
				Return r = new Return();
				r.addChild(binOp.getChild(0));
				this.addChild(r);
				return true;
			} // it is an operation. A return statement will be created with
				// this operation
		} else if (lastStatement instanceof Break
				|| lastStatement instanceof Print
				|| lastStatement instanceof If
				|| lastStatement instanceof While) {
			return false;
		}

		Return r = new Return();
		r.addChild(lastStatement);
		this.removeChild(this.getChildrenCount() - 1);
		this.addChild(r);
		return true;

	}

}