Lama

is a programming language developed by JetBrains Research for educational purposes as an exemplary language to introduce the domain of programming languages, compilers and tools. Its general characteristics are:

• procedural with first-class functions - functions can be passed as arguments, placed in data structures, returned and "constructed" at runtime via closure mechanism;
• with lexical static scoping;
• strict - all arguments of function application are evaluated before function body;
• imperative - variables can be re-assigned, function calls can have side effects;
• untyped - no static type checking is performed;
• with S-expressions and pattern-matching;
• with user-defined infix operators, including those defined in local scopes;
• with automatic memory management (garbage collection).

The name is an acronym for Lambda-Algol since the language has borrowed the syntactic shape of operators from Algol-68; Haskell and OCaml can be mentioned as other languages of inspiration.

The main purpose of is to present a repertoire of constructs with certain runtime behavior and relevant implementation techniques. The lack of a type system (a vital feature for a real-word language for software engineering) is an intensional decision which allows to show the unchained diversity of runtime behaviors, including those which a typical type system is called to prevent. On the other hand the language can be used in future as a raw substrate to apply various ways of software verification (including type systems) on.

The current implementation contains a native code compiler for x86-32, written in OCaml, a runtime library with garbage-collection support, written in C, and a small standard library, written in itself. The native code compiler uses gcc as a toolchain.

In addition, a source-level reference interpreter is implemented as well as a compiler to a small stack machine. The stack machine code can in turn be either interpreted on a stack machine interpreter, or used as an intermediate representation by the native code compiler.

Language Specification

The language specification can be found here.

Installation

Prerequisites:

• gcc-multilib
• ocaml (>= 4.07.1) [http://ocaml.org]
• opam (>= 2.0.4) [http://opam.ocaml.org]

Installing:

• opam pin add -n ostap https://github.com/dboulytchev/ostap.git#memoCPS (remember of "#" being a comment character in bash)
• opam pin add -y lama https://github.com/JetBrains-Research/Lama.git

Smoke-testing:

• pushd tutorial
• make
• popd