I have tagged the current state of the AlbaDsl project as v0.0.2 ahead of the Layla upgrade. The project supports the BCH 2026 features: Functions, Loops, Bitwise ops, and Pay to Script (P2S). See the updated readme below with links to Asciinema demo videos and example code.
AlbaDsl & AlbaVm
Experimental Haskell based tooling for Bitcoin Cash (BCH) contract development and testing.
AlbaDsl
AlbaDsl is an experimental statically typed functional “Forth” for Bitcoin Cash contract programming, implemented as a shallowly embedded Domain Specific Language (DSL) in Haskell. It is not a traditional Forth at all. The syntax is all Haskell, the language features are limited to what is reasonably expressable on CashVM, and inspiration comes from Haskell and functional programming. But at the core is postfix notation, a stack for argument passing, and an extensible collection of words (functions) — like Forth.
AlbaDsl’s abstraction mechanisms include macros (expressed using Haskell functions), functions (words), anonymous functions with partial application, and parametric polymorphism with type classes (to some degree). Collections of macros and functions can be grouped using standard Haskell modules and libraries. Contract complexity is managed by layering abstractions and taking advantage of the strong typing.
Haskell’s type system is used to statically enforce the type of the input and output stacks of a given AlbaDsl expression. Stack items can be assigned names (at the type-level) for easy reference. On top of the basic types offered by CashVM (TInt, TBytes, TBool, etc.) aggregated types such as TMaybe a, TEither a b, TTuple a b, and TVector a are implemented in the base library. These types are modeled after the corresponding types in Haskell. Building on this, users can construct their own abstract types. Type information is removed at compile time and is not present in the final bytecode.
Since an AlbaDsl program is a Haskell program, standard Haskell tooling such as syntax highlighting, linting, code formatting, and Language Server Protocol (LSP) are supported out of the box. The Haskell Language Server gives immediate feedback about type errors such as mismatched stack element types and can be used to interrogate the type of the stack at a given position in an expression.
AlbaVm
AlbaVm is a Bitcoin Cash virtual machine written in Haskell. It supports the CashVm 2026 instruction set. It passes the Libauth 2026 tests and various additional property based tests. AlbaVm can be used to evaluate arbitrary BCH byte code, and specifically AlbaDsl programs during development and testing.
By combining an AlbaDsl program/contract (p), the AlbaDsl compiler (compile), and the AlbaVm evaluator (eval), one can define a Haskell function f = eval (compile p). This function can be tested using standard Haskell unit test frameworks and property based testing such as QuickCheck. This then serves as testing of p.
Status
This code is experimental and work in progress. The AlbaDsl language is not fleshed out and the syntax and feature set continues to evolve. AlbaVm needs to be further tested. Example contracts need further validation. There will be bugs. For licensing, see LICENSE.
Demo Videos
- Introduction to AlbaDsl & AlbaVm. (Asciinema)
- Covers: Basic expressions, compilation and evaluation, type checking of expressions, LSP interaction, parameterized macros, QuickCheck testing, naming stack entries, and BigInt arithmetic.
- Functions and constants in AlbaDsl. (Asciinema)
- Covers: Defining functions and constants, listing program bytecode, and listing the function table.
Examples
AlbaDsl example code:
- wNAF elliptic curve scalar multiply on secp256k1. (GitHub)
- LZSS decompressor. Uses the CashVM 2026 bit shift operators. (GitHub) (BCR)
- Vector library. Vector that can store any type that implements the PackFs type class. (GitHub) (BCR)
- MergeSort. Sorts a Vector of elements satisfying the Ord typeclass. Uses recursion. (GitHub)
- TurtleVm: a meta-circular evaluator for Bitcoin Cash Script on CashVM 2025. (GitHub) (BCR)
- Beginnings of a standard library supporting TTuple, TMaybe, TEither, and some base type classes. (GitHub)
Example AlbaDsl contracts:
- Last will. Basic contract with three entry points. (GitHub)
- Elliptic Curve. Limited secp256k1 scalar multiply with a precomputed wNAF table in a BCH 2026 transaction. (GitHub)
- MiniTurtleVm Challenge. Meta-circular BCH Script evaluator inside a BCH 2025 Mainnet transaction. (GitHub) (BCR)
- Permutation Challenge. Illustrates shared libraries in read-only inputs on BCH 2026. (GitHub) (BCR)
Example AlbaVm HTML execution trace with function calls collapsed. (GitHub)
References
Original announcement: https://albadsl.github.io/alba-dsl/original-announcement.md