/// <summary>
/// Client
/// </summary>
/// <remarks>
/// Build a syntax tree representing a particular sentence in the language that the grammar defines.
/// </remarks>
public override void Execute()
{
var context = new Context();
// expression1 = 1 + 2
var expression1 = new AddExpression(new ConstantExpression(1), new ConstantExpression(2));
Assert.Equal(1 + 2, expression1.Solve(context));
// expression2 = 4 * 6
var expression2 = new MultiplyExpression(new ConstantExpression(4), new ConstantExpression(6));
Assert.Equal(4.0 * 6.0, expression2.Solve(context));
// expression3 = expression2 / 2
var expression3 = new DivideExpression(expression2, new ConstantExpression(2));
Assert.Equal(4.0 * 6.0 / 2.0, expression3.Solve(context));
// expression4 = expression1 - expression3
var expression4 = new SubtractExpression(new VariableExpression(nameof(expression1)), new VariableExpression(nameof(expression3)));
context.SetVariable(nameof(expression1), expression1);
context.SetVariable(nameof(expression3), expression3);
Assert.Equal((/* expression1 */ 1 + 2) - (/* expression3 */ 4.0 * 6.0 / 2.0), expression4.Solve(context));
// f(x) = ((5 * x) / 2) + ((2 ^ x) - 6)
// x = 6
var expression5 = new AddExpression(
new DivideExpression(
new MultiplyExpression(
new ConstantExpression(5),
new VariableExpression("x")),
new ConstantExpression(2)),
new SubtractExpression(
new PowerExpression(
new ConstantExpression(2),
new VariableExpression("x")),
new ConstantExpression(6)));
double x = 6;
context.SetVariable("x", new ConstantExpression(x));
Assert.Equal(((5 * x) / 2) + (Math.Pow(2, x) - 6), expression5.Solve(context));
}
