org.eclipse.epsilon.eol.dom.AssignmentStatement Maven / Gradle / Ivy

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/*********************************************************************
* Copyright (c) 2008 The University of York.
*
* This program and the accompanying materials are made
* available under the terms of the Eclipse Public License 2.0
* which is available at https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
**********************************************************************/
package org.eclipse.epsilon.eol.dom;

import java.util.List;
import java.util.Map;

import org.eclipse.epsilon.common.module.IModule;
import org.eclipse.epsilon.common.parse.AST;
import org.eclipse.epsilon.eol.exceptions.EolRuntimeException;
import org.eclipse.epsilon.eol.execute.ExecutorFactory;
import org.eclipse.epsilon.eol.execute.context.IEolContext;
import org.eclipse.epsilon.eol.execute.context.Variable;
import org.eclipse.epsilon.eol.execute.introspection.IPropertySetter;

public class AssignmentStatement extends Statement {
	
	protected Expression targetExpression;
	protected Expression valueExpression;
	
	public AssignmentStatement() {}
	
	public AssignmentStatement(Expression targetExpression, Expression valueExpression) {
		this.targetExpression = targetExpression;
		this.valueExpression = valueExpression;
	}
	
	@Override
	public void build(AST cst, IModule module) {
		super.build(cst, module);
		targetExpression = (Expression) module.createAst(cst.getFirstChild(), this);
		valueExpression = getValueExpression(cst, (Expression) module.createAst(cst.getSecondChild(), this));
	}
	
	/**
	 * 
	 * @param cst
	 * @return
	 * @since 2.2
	 */
	protected Expression getValueExpression(AST cst, Expression expression) {
		switch (cst.getText()) {
			case "+=":
				return new PlusOperatorExpression(targetExpression, expression);
			case "-=":
				return new MinusOperatorExpression(targetExpression, expression);
			case "/=":
				return new DivOperatorExpression(targetExpression, expression);
			case "*=":
				return new TimesOperatorExpression(targetExpression, expression);
			case "?=":
				return new ElvisOperatorExpression(targetExpression, expression);
			default:
				return expression;
		}
	}
	
	@Override
	public Object execute(IEolContext context) throws EolRuntimeException {	
		ExecutorFactory executorFactory = context.getExecutorFactory();
		
		Object valueExpressionResult;
			
		if (targetExpression instanceof PropertyCallExpression) {
			PropertyCallExpression pce = (PropertyCallExpression) targetExpression;
			Object source = executorFactory.execute(pce.getTargetExpression(), context);
			String property = pce.getName();
			IPropertySetter setter = context.getIntrospectionManager().getPropertySetterFor(source, property, context);
			valueExpressionResult = executorFactory.execute(valueExpression, context);
			Object value = getValueEquivalent(source, valueExpressionResult, context);
			try {
				setter.invoke(source, property, value, context);
			}
			catch (EolRuntimeException eox) {
				if (eox.getAst() == null) {
					eox.setAst(this);
				}
				throw eox;
			}
		}
		else if (targetExpression instanceof ItemSelectorExpression) {
			ItemSelectorExpression ise = (ItemSelectorExpression) targetExpression;
			Object source = executorFactory.execute(ise.getTargetExpression(), context);
			Object index = executorFactory.execute(ise.getIndexExpression(), context);
			valueExpressionResult = executorFactory.execute(valueExpression, context);
			Object value = getValueEquivalent(source, valueExpressionResult, context);
			
			if (source instanceof List) {
				if (!(index instanceof Integer)) 
					throw new EolRuntimeException("Collection index must be an integer but " + index + " was provided instead.", ise.getIndexExpression());
				else ((List) source).set((Integer) index, value);
			}
			else if (source instanceof Map) {
				((Map) source).put(index, value);
			}
			else {
				throw new EolRuntimeException(source + " is not a list or a map.", ise.getTargetExpression());
			}
		}
		else {
			Object targetExpressionResult;
			if (targetExpression instanceof NameExpression) {
				NameExpression ne = (NameExpression) targetExpression;
				targetExpressionResult = ne.execute(context, true);
			}
			else {
				targetExpressionResult = executorFactory.execute(targetExpression, context);
			}
			
			if (targetExpressionResult instanceof Variable) {
				Variable variable = (Variable) targetExpressionResult;
				valueExpressionResult = executorFactory.execute(valueExpression, context);
				try {
					Object value = getValueEquivalent(variable.getValue(), valueExpressionResult, context);
					variable.setValue(value, context);
				}
				catch (EolRuntimeException ex) {
					ex.setAst(targetExpression);
					throw ex;
				}
			}
			else {
				throw new EolRuntimeException("Internal error. Expected either a SetterMethod or a Variable and got an " + targetExpressionResult + " instead", this);
			}
		}
		
		return valueExpressionResult;
	}
	
	protected Object getValueEquivalent(Object source, Object value, IEolContext context) throws EolRuntimeException {
		return value;
	}
	
	public Expression getTargetExpression() {
		return targetExpression;
	}
	
	public void setTargetExpression(Expression targetExpression) {
		this.targetExpression = targetExpression;
	}
	
	public Expression getValueExpression() {
		return valueExpression;
	}
	
	public void setValueExpression(Expression valueExpression) {
		this.valueExpression = valueExpression;
	}
	
	public void accept(IEolVisitor visitor) {
		visitor.visit(this);
	}
}