Chasm.Utilities 2.5.2

Chasm.Utilities

Provides various utility types and methods.

Util

Contains various utility methods, that can be used to shorten common branch code. (or... you could also just not use the auto-formatting, and write everything in a single line, but that's not my style)

Util.Fail sets all out parameters to default and returns either false or a specified return value. Especially useful for parsing.

// Commonly written as:
if (stringIsInvalid) { result = null; return ErrorCode.InvalidString; }

// Using Util.Fail:
if (stringIsInvalid) return Util.Fail(ErrorCode.InvalidString, out result);

Util.Catch catches an exception thrown by the specified delegate. If the delegate returned a value, it can be read through an out parameter.

// Commonly written as:
object? result; Exception? ex;
try { result = doSomething(); ex = null; }
catch (Exception caught) { result = null; ex = caught; }

// Using Util.Catch:
var ex = Util.Catch(doSomething, out object? result);

Util.Is can be used to assign a type-casted value to an existing variable.

// Commonly written as:
if (a is string textA) { /* ... */ }
else if (b is string textB) { /* ... */ }
else if (c is string textC) { /* ... */ }

// Using Util.Is:
if (a is string text) { /* ... */ }
else if (Util.Is(b, out text)) { /* ... */ }
else if (Util.Is(c, out text)) { /* ... */ }

Util.With can be used to invoke functions while using a IDisposable:

// Commonly written as:
string? firstLine;
using (StreamReader reader = File.OpenText(path))
    firstLine = reader.ReadLine();

// Using Util.With:
string? firstLine = Util.With(File.OpenText(path), reader => reader.ReadLine());

Util.Swap just swaps two values. Useful when the tuple swap is too long or prone to errors.

// Commonly written as:
(firstVariable, secondVariable) = (secondVariable, firstVariable);

// Using Util.Swap:
Util.Swap(ref firstVariable, ref secondVariable);

DelegateDisposable

DelegateDisposable is a IDisposable interface implementation that invokes an action on disposal.

store.Subscribe(listenerFunc);
var listener = new DelegateDisposable(() => store.Unsubscribe(listenerFunc));

// Or like this, functional programming style:
var listener = DelegateDisposable.Create(
    () => store.Subscribe(listenerFunc),
    () => store.Unsubscribe(listenerFunc)
);

ReaderWriterLockSlimExtensions makes use of this class.

ReaderWriterLockSlim rwl = new();

// Commonly written as:
try
{
    rwl.EnterReadLock();
    /* ... */
}
finally
{
    rwl.ExitReadLock();
}

// Using ReaderWriterLockSlimExtensions:
using (rwl.WithReaderLock())
    /* ... */