private IExpression RelationalExpression()
{
var expression = AdditiveExpression();
while (lookAhead.Type == ExpressionTokenType.Less ||
lookAhead.Type == ExpressionTokenType.LessEqual ||
lookAhead.Type == ExpressionTokenType.Greater ||
lookAhead.Type == ExpressionTokenType.GreaterEqual)
{
var type = lookAhead.Type;
NextToken();
var rightOperand = AdditiveExpression();
switch (type)
{
case ExpressionTokenType.Less:
expression = new LessThan(expression, rightOperand);
break;
case ExpressionTokenType.LessEqual:
expression = new LessThanOrEquals(expression, rightOperand);
break;
case ExpressionTokenType.Greater:
expression = new GreaterThan(expression, rightOperand);
break;
case ExpressionTokenType.GreaterEqual:
expression = new GreaterThanOrEquals(expression, rightOperand);
break;
}
}
return(expression);
}
public void Evaluate_LeftIsGreaterThanThanRight_ReturnsFalse()
{
var left = new Integer(5000);
var right = new Integer(3934);
var expr = new LessThanOrEquals(left, right);
var result = expr.EvaluateWithData <bool>();
Assert.False(result);
}
public void Evaluate_LeftIsEqualToRight_ReturnsTrue()
{
var left = new Integer(3934);
var right = new Integer(3934);
var expr = new LessThanOrEquals(left, right);
var result = expr.EvaluateWithData <bool>();
Assert.True(result);
}
public void ToString_IntegerComparison_ReturnsExpected()
{
var expr = new LessThanOrEquals(new Integer(3), new Integer(9));
Assert.AreEqual("3 <= 9", expr.ToString());
}