public void SubtractionOperator()
{
string eq = " 1 - 4";
Lexer tokenizer = new Lexer();
List <Token> tokens = tokenizer.Parse(eq);
TokenVerifier verifier = new TokenVerifier();
Assert.IsTrue(verifier.Verify(tokens));
TokenEvaluator evaluator = new TokenEvaluator();
Assert.AreEqual(-3, evaluator.Evaluate(tokens));
}
public void MultiplicationOperator()
{
string eq = "5*10";
int expected = 50;
Lexer tokenizer = new Lexer();
List <Token> tokens = tokenizer.Parse(eq);
TokenVerifier verifier = new TokenVerifier();
Assert.IsTrue(verifier.Verify(tokens));
TokenEvaluator evaluator = new TokenEvaluator();
double actual = evaluator.Evaluate(tokens);
Assert.AreEqual(expected, actual);
}
public void AdditionOperator()
{
string eq = " 1.5 + 4.0";
double expected = 5.5;
Lexer tokenizer = new Lexer();
List <Token> tokens = tokenizer.Parse(eq);
TokenVerifier verifier = new TokenVerifier();
Assert.IsTrue(verifier.Verify(tokens));
TokenEvaluator evaluator = new TokenEvaluator();
double actual = evaluator.Evaluate(tokens);
Assert.AreEqual(expected, actual);
}
public void AdditionAndDiceOperator()
{
string eq = "1d5 + 10";
int lowBound = 11;
int highBound = 15;
Lexer tokenizer = new Lexer();
List <Token> tokens = tokenizer.Parse(eq);
TokenVerifier verifier = new TokenVerifier();
Assert.IsTrue(verifier.Verify(tokens));
TokenEvaluator evaluator = new TokenEvaluator();
double results = evaluator.Evaluate(tokens);
if (!(lowBound <= results && results <= highBound))
{
Assert.Fail(String.Format("Result should have fallen within {0} and {1} but was instead {2}", lowBound, highBound, results));
}
}
public static string GetTableName(string commandText)
{
var handler = new CommandTextHandler();
var evaluator = new TokenEvaluator(handler);
evaluator.Evaluate(commandText);
if (handler.Command.Type != "Select")
{
return(string.Empty);
}
var fromTable = handler.From.Items.FirstOrDefault();
if (string.IsNullOrEmpty(fromTable) || fromTable.EndsWith(","))
{
return(string.Empty);
}
return(fromTable);
}
/// <summary>
/// Evaluates a mathematical expression. Only + - * / are supported.
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public static int Evaluate(string expression)
{
return(_evaluator.Evaluate(_parser.Parse(expression).ToList().InfixToPostfix()));
}
