public async Task IsExpressionVisitorResultEqualToCompiledExpression(string expression)
{
var serviceCollection = new ServiceCollection();
serviceCollection.AddScoped <ICalculator, DirectCalculator>();
var compiledResult = Expression.Lambda <Func <double> >(ExpressionTreeBuilder.Build(expression)).Compile()();
var visitorResult = await CalculatorExpression.Calculator.CalculateAsync(expression, serviceCollection);
Assert.Equal(compiledResult, visitorResult);
}
/// <summary>
/// Evaluates the result value for the provided math expression.
/// </summary>
/// <param name="s">Input string (math expression in Infix notation).</param>
/// <returns>Result of evaluation of the expression.</returns>
public double Evaluate(string s)
{
if (string.IsNullOrEmpty(s))
{
throw new ArgumentException("Value cannot be null or empty.", nameof(s));
}
var builder = new ExpressionTreeBuilder();
var expr = builder.Build(s);
var visitor = new MathExpressionVisitor();
var result = visitor.Visit(expr);
return(result);
}
public void CanBuildExpressionTree()
{
var input = new List <Token>()
{
new Token {
Type = TokenType.Number, Value = 5
},
new Token {
Type = TokenType.Add, Value = null
},
new Token {
Type = TokenType.Number, Value = 7
},
};
var expectedOutput = new NodeAdd
{
Left = new NodeNumber {
Value = 5
},
Right = new NodeNumber {
Value = 7
}
};
var root = ExpressionTreeBuilder.Build(input) as NodeAdd;
Assert.NotNull(root);
var left = root.Left as NodeNumber;
Assert.NotNull(left);
Assert.Equal(5, left.Value);
var right = root.Right as NodeNumber;
Assert.NotNull(right);
Assert.Equal(7, right.Value);
}
