issue 42 : ensure runtime type of variable definition is kept

plugins/org.yakindu.sct.simulation.core.sexec/src/org/yakindu/sct/simulation/core/sexec/interpreter/StextStatementInterpreter.xtend

@@ -106,19 +106,29 @@ class StextStatementInterpreter extends AbstractStatementInterpreter {
 		if(ts.isRealType(type)) return Double.valueOf(value)
 		throw new IllegalArgumentException
 	}
+	def dispatch Object typeCast(Boolean value, Type type) {
+		if(ts.isBooleanType(type)) return value
+		throw new IllegalArgumentException
+	}
+	
+	def dispatch Object typeCast(String value, Type type) {
+		if(ts.isStringType(type)) return value
+		throw new IllegalArgumentException
+	}
 
 	def dispatch Object typeCast(Object value, Type type) {
-		throw new IllegalArgumentException("Invalid cast")
+		throw new IllegalArgumentException("Invalid cast " + value.class + " to " + type.name)
 	}
 
 	def Object executeAssignment(AssignmentExpression assignment) {
 		var scopeVariable = context.resolve(assignment.varRef)
 		var result = assignment.expression.execute
 		if (assignment.operator == AssignmentOperator::ASSIGN) {
-			scopeVariable.value = result
+			//Strong typing, use the type of the scopeVariable instead of using new runtime type
+			scopeVariable.value = typeCast(result, scopeVariable.type.type)
 		} else {
 			var operator = AbstractStatementInterpreter::assignFunctionMap.get(assignment.operator.getName())
-			scopeVariable.value = evaluate(operator, scopeVariable.getValue, result)
+			scopeVariable.value = typeCast(evaluate(operator, scopeVariable.getValue, result),scopeVariable.type.type)
 		}
 		scopeVariable.value
 	}
@@ -295,7 +305,7 @@ class StextStatementInterpreter extends AbstractStatementInterpreter {
 	}
 
 	def dispatch valueLiteral(HexLiteral literal) {
-		return literal.value
+		return literal.value as long
 	}
 
 	def dispatch valueLiteral(BoolLiteral bool) {

test-plugins/org.yakindu.sct.simulation.core.sexec.test/src/org/yakindu/sct/model/sexec/interpreter/test/util/AbstractExecutionFlowTest.java

@@ -60,9 +60,9 @@ public abstract class AbstractExecutionFlowTest {
 		return (Boolean) variable.getValue();
 	}
 
-	protected Float getReal(String varName) {
+	protected Double getReal(String varName) {
 		ExecutionVariable variable = context().getVariable(varName);
-		return (Float) variable.getValue();
+		return (Double) variable.getValue();
 	}
 
 	protected String getString(String varName) {