private static EvaluateExpressionDelegate Evaluator(Func <IReadOnlyList <object>, bool> function, FunctionUtils.VerifyExpression verify)
{
return((expression, state, options) =>
{
var result = false;
string error = null;
IReadOnlyList <object> args;
(args, error) = FunctionUtils.EvaluateChildren(expression, state, new Options(options)
{
NullSubstitution = null
}, verify);
if (error == null)
{
// Ensure args are all of same type
bool?isNumber = null;
foreach (var arg in args)
{
var obj = arg;
if (isNumber.HasValue)
{
if (obj != null && obj.IsNumber() != isNumber.Value)
{
error = $"Arguments must either all be numbers or strings in {expression}";
break;
}
}
else
{
isNumber = obj.IsNumber();
}
}
if (error == null)
{
try
{
result = function(args);
}
#pragma warning disable CA1031 // Do not catch general exception types (we are capturing the exception and returning it)
catch (Exception e)
#pragma warning restore CA1031 // Do not catch general exception types
{
// NOTE: This should not happen in normal execution
error = e.Message;
}
}
}
else
{
// Swallow errors and treat as false
error = null;
}
return (result, error);
});
}
public ComparisonEvaluator(string type, Func <IReadOnlyList <object>, bool> function, ValidateExpressionDelegate validator, FunctionUtils.VerifyExpression verify = null)
: base(type, Evaluator(function, verify), ReturnType.Boolean, validator)
{
}
/// <summary>
/// Initializes a new instance of the <see cref="MultivariateNumericEvaluator"/> class.
/// </summary>
/// <param name="type">Name of the function.</param>
/// <param name="function"> The multivariate numeric function, it takes a list of objects as input and returns an object.</param>
/// <param name = "verify" > Optional function to verify each child's result.</param>
public MultivariateNumericEvaluator(string type, Func <IReadOnlyList <object>, object> function, FunctionUtils.VerifyExpression verify = null)
: base(type, Evaluator(function, verify), ReturnType.Number, FunctionUtils.ValidateTwoOrMoreThanTwoNumbers)
{
}
private static EvaluateExpressionDelegate Evaluator(Func <IReadOnlyList <object>, object> function, FunctionUtils.VerifyExpression verify = null)
{
return(FunctionUtils.ApplySequence(function, verify ?? FunctionUtils.VerifyNumber));
}
private static EvaluateExpressionDelegate Evaluator(Func <IReadOnlyList <object>, bool> function, FunctionUtils.VerifyExpression verify)
{
return((expression, state, options) =>
{
var result = false;
string error = null;
IReadOnlyList <object> args;
(args, error) = FunctionUtils.EvaluateChildren(expression, state, new Options(options)
{
NullSubstitution = null
}, verify);
if (error == null)
{
try
{
result = function(args);
}
#pragma warning disable CA1031 // Do not catch general exception types (we are capturing the exception and returning it)
catch (Exception e)
#pragma warning restore CA1031 // Do not catch general exception types
{
// NOTE: This should not happen in normal execution
error = e.Message;
}
}
else
{
// Swallow errors and treat as false
error = null;
}
return (result, error);
});
}