Amalgam® Overview

Amalgam is a domain specific language (DSL) developed primarily for genetic programming and instance based machine learning, but also for simulation, agent based modeling, data storage and retrieval, the mathematics of probability theory and information theory, and game content and AI. The language format is somewhat LISP-like in that it uses parenthesized list format with prefix notation and is geared toward functional programming, where there is a one-to-one mapping between the code and the corresponding parse tree.

Whereas virtually all practical programming languages are primarily designed for some combination of programmer productivity and computational performance, Amalgam prioritizes code matching and merging, as well as a deep equivalence of code and data. Amalgam uses entities to store code and data, with a rich query system to find entities by their labels. The language uses a variable stack, but all attributes and methods are stored directly as labels in entities. There is no separate class versus instance, but entities can be used as prototypes to be copied and modified. Though code and data are represented as trees from the root of each entity, graphs in code and data structures are permitted and are flattened to code using special references. Further, instead of failing early when there is an error, Amalgam supports genetic programming and code mixing by being extremely weakly typed, and attempts to find a way to execute code no matter whether types match or not.

Amalgam takes inspiration from many programming languages, but those with the largest influence are LISP, Scheme, Haskell, Perl, Smalltalk, and Python. Despite being much like LISP, there is deliberately no macro system. This is to make sure that code is semantically similar whenever the code is similar, regardless of context. It makes it easy to find the difference between x and y as an executable patch, and then apply that patch to z as (call (difference x y) {_ z}), or semantically mix blocks of code a and b as (mix a b). Amalgam is not a purely functional language. It has imperative and object oriented capabilities, but is primarily optimized for functional programming with relatively few opcodes that are functionally flexible based on parameters to maximize flexibility with code mixing and matching.

Genetic programming can create arbitrary code, so there is always a chance that an evolved program ends up consuming more CPU or memory resources than desired, or may attempt to affect the system outside of the interpreter. For these reasons, there are many strict sandboxing aspects of the language with optional constraints on access, CPU, and memory. Amalgam also has a rich permissions system, which controls what entities and code are able to do, whether writing to the console or executing system commands.

The Amalgam interpreter was designed to be used a standalone interpreter and to build functionality for other programming languages and environments. It does not currently have rich support for linking C libraries into the language, but that is planned for future functionality.

Initial development on Amalgam began in 2011. It was first offered as a commercial product in 2014 at Hazardous Software Inc. and was open sourced in September 2023 by Howso Incorporated (formerly known as Diveplane Corporation, a company spun out of Hazardous Software Inc.).

When referencing the language: “Amalgam”, “amalgam”, “amalgam-lang”, and “amalgam language” are used interchangeably with Amalgam being preferred. When referencing the interpreter: “Amalgam interpreter”, “interpreter”, “Amalgam app”, and “Amalgam lib” are used interchangeably.