Open Source Scala Programming Languages

Scala 3 is the latest major release of the Scala language—featuring a complete compiler rewrite (Dotty), new syntax with optional braces and given/using contextual abstractions, union/intersection types, opaque types, first-class enums, and better type inference. It unifies object-oriented and functional programming paradigms into a safer, more expressive language running on the JVM with full Java interoperability.

Flix is a statically typed programming language combining functional, imperative, and logic paradigms, with first‑class Datalog constraints and a polymorphic effect system. Designed to run on the JVM, Flix enforces purity tracking at compile time, supports algebraic data types, tail‑call elimination, and allows entire Datalog programs as values.

ArnoldC is a programming language built as a joke language, where the entire syntax is based on quotes from Arnold Schwarzenegger movies. Instead of conventional keywords and operators, it uses memorable movie lines to represent programming constructs like conditionals, loops, and functions. For example, “IT’S SHOWTIME” starts the main method, “TALK TO THE HAND” represents output, and “I’LL BE BACK” denotes a return statement. While humorous in nature, the language is fully functional and can be used to write real programs, showcasing how flexible compiler and interpreter design can be. The project is a playful experiment in esoteric programming languages, intended to entertain developers while also serving as an example of how language parsing and compilation can work with unconventional syntax. It demonstrates the overlap between pop culture and software development, turning famous lines into executable logic.

SpinalHDL is a hardware description (HDL) framework embedded in Scala, enabling hardware designers to build digital circuits with modern programming abstractions. Instead of writing in Verilog or VHDL directly, users describe hardware components and their interconnects using Scala code and Spinal’s domain-specific library, which then emits synthesizable hardware (e.g. as Verilog). Because SpinalHDL is embedded in Scala, it allows reuse of functional abstractions, parameterization, modular composition, and higher-level constructs to manage complexity. It supports building systems at various levels—single modules, pipelines, memories, controllers, etc.—while letting the designer control timing, pipelining, and resource sharing explicitly. The generated hardware can be synthesized for FPGAs or ASIC flows, making it practical for real designs.

Vale is a systems programming language and compiler that strives to combine performance, safety, and ease in a way that avoids many of the complexities of traditional memory management techniques. It is ahead-of-time (AOT) compiled, targeting LLVM as a backend, and is statically typed. The language introduces a concept called generational references to provide memory safety without relying on a garbage collector, and aims for “safe without a borrow checker” (i.e. reducing the burden on the programmer). Vale also pursues what they call Fearless FFI to make foreign function interface (e.g. interoperating with C libraries) safer and less error-prone. The language supports single ownership semantics (so values have a unique owner, which simplifies reasoning) while also enabling aliasing under controlled circumstances.