μRT (urt)

μRT (microRuntime) is a small and lightweight runtime library for the D programming language, designed for realtime and embedded systems. It is an alternative to the standard D runtime (druntime) and Phobos standard library, with a focus on minimalism, performance, and predictability.

Features

• No Garbage Collection: urt is designed to work without a garbage collector, making it suitable for systems with strict memory constraints.
• Lightweight: The library is small and has minimal dependencies, reducing the overall footprint of your application.
• Real-time Capable: urt is designed with real-time systems in mind, providing predictable performance and low latency.

Getting Started

To use urt in your D project, simply add it as a dependency in your dub.json file:

{
  "dependencies": {
    "urt": "~>0.1.0"
  }
}

Class casts

Class identity conversions and upcasts use the static source and target types. Downcasts require a Source.dyn_cast!Target(source) contract; there is no fallback to compiler TypeInfo. The contract must return a value convertible to the target type, preserve qualifiers, and be nothrow @nogc. An incompatible object returns null. Null inputs bypass the contract at runtime, but still require a valid contract at compile time.

A hierarchy can expose its existing checked cast function with an inherited alias on its root class:

alias dyn_cast = application.types.checked_cast;

The function takes the source reference explicitly, so application metadata and ancestry checks stay in the application. The contract must not implement itself with the same D downcast, which would recurse.

Throwable supplies no downcast contract. All Makefile targets default to NOEXCEPTIONS=1; LDC also uses --fno-exceptions. Compiler-generated throw entry points terminate, and Windows retains stack-trace capture and symbol resolution. Setting NOEXCEPTIONS=0 includes the unsupported legacy exception runtime and fails at its Throwable-to-Error cast.

Class-to-interface dynamic casts remain unsupported by this class-cast contract.

License

This project is licensed under the MIT License - see the LICENSE file for details.