TedToolkit.Quantities 2026.4.8

TedToolkit.Quantities

A type-safe, source-generated quantities and units library for .NET. Define a partial struct, and the Roslyn analyzer generates unit conversions, arithmetic operators, formatting, and more — all backed by the QUDT ontology.

Features

• Source-generated — zero reflection, zero runtime overhead; everything is produced at compile time
• Type-safe operators — Angle / Angle yields DimensionlessRatio, Angle * Length yields Length, etc.
• Broad framework support — .NET 6–10, .NET Framework 4.7.2+, .NET Standard 2.0/2.1
• QUDT-backed — units and conversion factors come from the W3C QUDT ontology
• Multiple quantity systems — SI, CGS, Imperial, US Customary, ISQ, Planck, and more
• Tolerance-aware comparisons — configurable precision for equality and ordering via scoped Tolerance

Quick Start

Install the package:

dotnet add package TedToolkit.Quantities

Define a Quantity

Declare a partial struct in the TedToolkit.Quantities namespace. The source generator fills in the rest:

using TedToolkit.Quantities;

[QuantityDisplayUnit<AngleUnit>(AngleUnit.Degree)]
[QuantityOperator<Angle, Angle, DimensionlessRatio>(Operator.DIVIDE)]
[QuantityOperator<Angle, Angle, Angle>(Operator.SUBTRACT)]
[QuantityOperator<Angle, Length, Length>(Operator.MULTIPLY)]
public partial struct Angle;

Create and Convert

// From a constructor
var angle = new Angle(180.0, AngleUnit.Degree);

// From a static factory
var angle2 = Angle.FromRadian(Math.PI);

// From an extension property on double
var angle3 = 90.0.Degree;

// Convert between units
double rad = angle.As(AngleUnit.Radian);   // π
double deg = angle.Degree;                  // 180.0

Arithmetic

var a = 90.0.Degree;
var b = 45.0.Degree;

Angle sum  = a + b;            // 135°
Angle diff = a - b;            // 45°
Angle half = a / 2.0;          // 45°

// Cross-quantity operators (defined via attributes)
DimensionlessRatio ratio = a / b;   // 2.0

Formatting

var angle = 45.0.Degree;

angle.ToString();                                    // "45 °"
angle.ToString(AngleUnit.Radian, "F4");              // "0.7854 rad"

Tolerance

Quantity comparisons use a scoped Tolerance so floating-point results can be compared meaningfully:

using TedToolkit.Scopes;

using (new Tolerance { Angle = 1e-9 }.FastPush())
{
    var a = Angle.FromDegree(360.0);
    var b = Angle.FromRadian(2 * Math.PI);
    Console.WriteLine(a == b);  // True
}

Attributes Reference

Quantity Systems

The library ships with unit data for multiple systems via QuantitySystems:

License

LGPL-3.0 — see COPYING and COPYING.LESSER.