private IExpression ParseBinaryExpression(int level)
{
if (level >= binaryoperators.Length)
{
return(this.ParseTerm());
}
IExpression expr = this.ParseBinaryExpression(level + 1);
if (expr == null)
{
return(null);
}
Token token;
for (token = this.lexer.NextToken(); token != null && this.IsBinaryOperator(level, token); token = this.lexer.NextToken())
{
if (token.Value == "=:=")
{
expr = new StrictEqualExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "==")
{
expr = new EqualExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "+")
{
expr = new AddExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "-")
{
expr = new SubtractExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "*")
{
expr = new MultiplyExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "/")
{
expr = new DivideExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "div")
{
expr = new DivExpression(expr, this.ParseBinaryExpression(level + 1));
}
else if (token.Value == "rem")
{
expr = new RemExpression(expr, this.ParseBinaryExpression(level + 1));
}
}
if (token != null)
{
this.lexer.PushToken(token);
}
return(expr);
}
public void RaiseIfRemainderRealByInteger()
{
RemExpression expr = new RemExpression(new ConstantExpression(6.5), new ConstantExpression(2));
try
{
expr.Evaluate(null);
Assert.Fail();
}
catch (Exception ex)
{
Assert.IsInstanceOfType(ex, typeof(InvalidCastException));
}
}
public void ParseSimpleRem()
{
Parser parser = new Parser("10 rem 20.");
IExpression expression = parser.ParseExpression();
Assert.IsNotNull(expression);
Assert.IsInstanceOfType(expression, typeof(RemExpression));
RemExpression remexpression = (RemExpression)expression;
Assert.IsInstanceOfType(remexpression.LeftExpression, typeof(ConstantExpression));
Assert.IsInstanceOfType(remexpression.RightExpression, typeof(ConstantExpression));
Assert.AreEqual(10, ((ConstantExpression)remexpression.LeftExpression).Value);
Assert.AreEqual(20, ((ConstantExpression)remexpression.RightExpression).Value);
}
public void NonZeroRemainderOfTwoIntegers()
{
RemExpression expr = new RemExpression(new ConstantExpression(5), new ConstantExpression(2));
Assert.AreEqual(1, expr.Evaluate(null));
}
