ICResult

A simple alternate to checked exceptions for applications where exceptions would not be appropriate.

This attempts to solve two problems. First of all it removes the requirement to supply output parameters from all methods which return a value as well as an error. For example:

bool tryGetValue(float& out_value);

Secondly it reduces the loss of context that often occurs in methods like this. When false is returned an error presumably occurred internally, but we have no access to what caused it.

Some systems may print the internal error to the console, however this becomes a problem when the consumer of the method gracefully handles the error. The printed internal error is now no longer relevant and becomes spam. It can obscure other genuine errors.

To resolve these issues a Result can be used. This provides the means to return either an output value or an error.

Result<float, ErrorEnum> tryGetValue();

In the case of an error a description can be provided, reducing loss of context. In addition, if the error was caused by another, it can also be returned through the Result. The user can then use getFullErrorMessage() to print the current error descripion and, recursively, the errors that caused it.

3 convenience typedefs have also been supplied: Error, BoolResult and BoolError. Error is used when no return value is needed, bool is a specialisation for results that use a bool error, and BoolError combines both cases.

BoolResult<float> tryGetValue();
Error<ErrorEnum> tryGetValue();
BoolError tryGetValue();

Code Example

#include <iostream>
#include <time.h>
#include "ICResult/Result.h"

enum class OperationResult
{
	k_success,
	k_failedOperation,
	k_operationNotStarted
};

IC::BoolResult<float> tryCalcValue()
{
	if (rand() % 2 == 0)
	{
		return IC::BoolResult<float>(5.5f);
	}

	return IC::BoolResult<float>(false, "Could not calculate value.");
}

IC::Result<float, OperationResult> tryPerformOperation()
{
	if (rand() % 2 == 0)
	{
		auto result = tryCalcValue();
		if (result)
		{
			return IC::Result<float, OperationResult>(result.getValue());
		}

		return IC::Result<float, OperationResult>(OperationResult::k_failedOperation, "The operation could not be performed.", result);
	}

	return IC::Result<float, OperationResult>(OperationResult::k_operationNotStarted, "Failed to start operation.");
}

int main()
{
	auto result = tryPerformOperation();
	if (result)
	{
		std::cout << "The result of the operation is: " << result.getValue();
	}
	else
	{
		std::cout << result.getFullErrorMessage();
	}
}