private void GivenInput(string input, EvaluationContext context = null)
{
if (context == null) { context = new EvaluationContext(null); }
_input = input;
_result = new Evaluator(context).EvaluateInfix(input).Value;
}
/// <summary>
/// Initializes a new instance of the <see cref="Evaluator"/> class.
/// </summary>
/// <param name="context">The context.</param>
/// <exception cref="System.ArgumentNullException">context</exception>
public Evaluator(EvaluationContext context)
{
if (context == null) { throw new ArgumentNullException("context"); }
_context = context;
}
public void Support_Custom_Function()
{
var ctx = new EvaluationContext(null);
ctx.RegisterFunction("always5", new FunctionRoutine(0, (c, p) => new ExpressionToken("5")));
GivenInput("10 + always5()", ctx);
ExpectResult("15");
}
/// <summary>
/// Evaluates using the function routine.
/// </summary>
/// <param name="context">The context.</param>
/// <param name="args">The arguments.</param>
/// <returns></returns>
public ExpressionToken Evaluate(EvaluationContext context, ExpressionToken[] args) { return _routine(context, args); }
/// <summary>
/// Converts to the decimal value.
/// </summary>
/// <returns></returns>
/// <exception cref="System.NotSupportedException"></exception>
/// <exception cref="FormatException"></exception>
public decimal ToDecimal(EvaluationContext context)
{
switch (TokenType)
{
case ExpressionTokenType.Value:
case ExpressionTokenType.SingleQuoted:
case ExpressionTokenType.DoubleQuoted:
return decimal.Parse(Value, CultureInfo.CurrentCulture);
case ExpressionTokenType.Field:
if (context == null) { throw new ArgumentNullException("context"); }
return decimal.Parse(context.GetFieldValue(Value).ToString(), CultureInfo.CurrentCulture);
default:
throw new NotSupportedException(string.Format(CultureInfo.InvariantCulture, "Cannot convert {0}({1}) to a numeric value.", TokenType, Value));
}
}
/// <summary>
/// Gets value as string with resolution.
/// </summary>
/// <param name="context">The context.</param>
/// <returns></returns>
public string ToString(EvaluationContext context)
{
switch (TokenType)
{
case ExpressionTokenType.Field:
if (context == null) { throw new ArgumentNullException("context"); }
return context.GetFieldValue(Value).ToString();
default:
return Value;
}
}
