Class Error<T>

Error holds either a value of type T or an exception.
Inheritance
System.Object
Error<T>
Inherited Members
System.Object.Equals(System.Object, System.Object)
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: Maki
Assembly: Maki.dll
Syntax
public class Error<T>
Type Parameters
Name Description
T Type of value.
Examples
The following example shows how to use Error to store either a value or an exception. 
using Maki;
using System;

namespace Samples
{
    class Program
    {
        // Either returns an int or throws an exception
        static int ReturnValueOrThrow()
        {
            var value = new Random().Next(100);
            return value < 50 ? value : throw new Exception();
        }

        static void Main(string[] args)
        {
            // Call function, value holds either an int or an exception
            Error<int> value = Error.Make(ReturnValueOrThrow);

            if (value.HasValue)
            {
                value = value.Get() * 2;
                Console.WriteLine(value.Get());
            }
            else // value.IsException
            {
                // Get exception from value, can handle or rethrow
                throw value.Exception();
            }
        }
    }
}

Constructors

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Error(T)

Creates a new Error from the given item.
Declaration
public Error(T item)
Parameters
Type Name Description
T item Item to initialize the error with.
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Error(Exception)

Creates a new Error from the given exception.
Declaration
public Error(Exception e)
Parameters
Type Name Description
System.Exception e Exception to initialize Error with.

Properties

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HasValue

True if Error contains a value.
Declaration
public bool HasValue { get; }
Property Value
Type Description
System.Boolean
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IsError

True if Error contains an exception.
Declaration
public bool IsError { get; }
Property Value
Type Description
System.Boolean

Methods

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Equals(Object)

Determines whether the specified object is equal to the current object.
Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
System.Object obj The object to compare with the current object.
Returns
Type Description
System.Boolean True if the objects are equal.
Overrides
System.Object.Equals(System.Object)
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Exception()

Gets the exception inhabiting the Error.
Declaration
public Exception Exception()
Returns
Type Description
System.Exception Exception inhabiting the Error.
Exceptions
Type Condition
System.InvalidCastException Thrown if the Error contains an exception.
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Get()

Gets the value inhabiting the Error.
Declaration
public T Get()
Returns
Type Description
T Value inhabiting the Error.
Exceptions
Type Condition
System.InvalidCastException Thrown if the Error contains an exception.
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GetHashCode()

Returns the hash code for this instance.
Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32 Hash code.
Overrides
System.Object.GetHashCode()
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MakeException(Exception)

Creates a new Error containing an exception.
Declaration
public static Error<T> MakeException(Exception e)
Parameters
Type Name Description
System.Exception e Exception to hold in the new Error.
Returns
Type Description
Error<T> Error containing the given exception.
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MakeValue(T)

Creates a new Error containing a value.
Declaration
public static Error<T> MakeValue(T item)
Parameters
Type Name Description
T item Item to hold in the new Error.
Returns
Type Description
Error<T> Error containing the given item.

Operators

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Explicit(Error<T> to T)

Explicit cast from Error to type T.
Declaration
public static explicit operator T(Error<T> error)
Parameters
Type Name Description
Error<T> error Error to cast from.
Returns
Type Description
T
Exceptions
Type Condition
System.InvalidCastException Thrown if the Error doesn't contain a value.
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Explicit(Error<T> to Exception)

Explicit cast from Error to Exception.
Declaration
public static explicit operator Exception(Error<T> error)
Parameters
Type Name Description
Error<T> error Error to cast from.
Returns
Type Description
System.Exception
Exceptions
Type Condition
System.InvalidCastException Thrown if the Error doesn't contain an exception.
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Implicit(T to Error<T>)

Implicit cast from type T to Error.
Declaration
public static implicit operator Error<T>(T item)
Parameters
Type Name Description
T item Item to cast from.
Returns
Type Description
Error<T>
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Implicit(Exception to Error<T>)

Implicit cast from Exception to Error.
Declaration
public static implicit operator Error<T>(Exception e)
Parameters
Type Name Description
System.Exception e Exception to cast from.
Returns
Type Description
Error<T>

Extension Methods