public void EvaluateCompareExpression()
{
CompareExpression expression = new CompareExpression(ComparisonOperator.Equal, new ConstantExpression(1), new ConstantExpression(2));
var result = expression.Evaluate(null);
Assert.IsInstanceOfType(result, typeof(bool));
Assert.IsFalse((bool)result);
Assert.AreEqual(ComparisonOperator.Equal, expression.Operation);
}
public void CreateAndEvaluateSimpleWhileCommand()
{
BindingEnvironment environment = new BindingEnvironment();
environment.SetValue("a", 1);
IExpression condition = new CompareExpression(ComparisonOperator.Less, new NameExpression("a"), new ConstantExpression(10));
ICommand body = new SetCommand("a", new BinaryOperatorExpression(new NameExpression("a"), new ConstantExpression(1), BinaryOperator.Add));
WhileCommand command = new WhileCommand(condition, body);
command.Execute(environment);
Assert.AreEqual(condition, command.Condition);
Assert.AreEqual(body, command.Command);
Assert.AreEqual(10, environment.GetValue("a"));
}
private IExpression CompileBinaryLevel0Expression()
{
IExpression expression = this.CompileBinaryLevel1Expression();
if (expression == null)
return null;
Token token = this.lexer.NextToken();
while (IsLevel0Operator(token))
{
IExpression expression2 = this.CompileBinaryLevel1Expression();
expression = new CompareExpression(CompileCompareOperator(token.Value), expression, expression2);
token = this.lexer.NextToken();
}
if (token != null)
this.lexer.PushToken(token);
return expression;
}