🐆 Bars

Bars (барс) — Снежният леопард. Бърз, независим, опасен.The snow leopard (Panthera uncia)

A systems programming language with Clojure syntax, Rust-like ownership (lighter), and compilation to native code via QBE, Cranelift, and LLVM.

;; examples/hello.brs
(defn main []
  (println "Hello, World!"))

$ bars run examples/hello.brs
Hello, World!

---

Why Bars?

• Clojure syntax — parentheses naturally express scope and structure. Only () and [] brackets.
• Lightweight ownership — NLL borrow checking, drop checking, no lifetime annotations.
• Type inference — Hindley-Milner type system with bars check --types.
• Three backends — QBE for fast AOT, Cranelift for JIT/REPL and fast AOT, LLVM for --release.
• Lambda functions — anonymous (fn [x] body) with full pipeline support.
• Zero-cost FFI — direct C ABI access through the runtime.
• GC when you want it — stack + ownership + Boehm GC for complex data.
• .brs — source file extension.

---

Quick Start

Prerequisites

• Rust 1.70+ (for building the compiler)
• qbe (AOT backend, installed at ~/.local/bin/qbe or on PATH)
• libgc-dev (Boehm GC for the runtime)
• cc / gcc (for linking)

Build

git clone https://codeberg.org/bars-lang/bars-lang.git
cd bars-lang
cargo build --release

Run

# Read and print AST
bars read examples/hello.brs

# Compile to QBE IR
bars build examples/hello.brs

# Compile and run (default QBE backend)
bars run examples/math.brs

# Compile and run with Cranelift backend
bars run --backend cranelift examples/math.brs

# REPL (Cranelift JIT)
bars repl

---

Language Tour

Functions

(defn greet [name]
  (println name))

(defn add [a b]
  (+ a b))

Variables

(defn main []
  (let [x 42
        y (+ x 1)]
    (println y)))

Conditionals

(defn main []
  (let [x 2]
    (cond
      (= x 1) "one"
      (= x 2) "two"
      :else   "other")))

Loops

(defn factorial [n]
  (loop [i n acc 1]
    (if (= i 0)
      acc
      (recur (- i 1) (* acc i)))))

Vectors

(defn main []
  (let [v (vector 1 2 3)]
    (push v 4)
    (println (count v))        ;; 4
    (println (get v 2))))      ;; 3

Vectors can be nested:

(def v [1 [2 3] 4])
(println (get (get v 1) 0))  ;; 2

Maps

Maps are created with functions (no {} literal syntax):

(defn main []
  (let [m (map)]
    (map-set m 1 100)
    (println (map-get m 1))))  ;; 100

Maps can hold vectors as values:

(def m (map))
(map-set m 1 [10 20])
(println (get (map-get m 1) 0))  ;; 10

Sets

(defn main []
  (let [s (set)]
    (set-add s 1)
    (set-add s 2)
    (println (set-count s))          ;; 2
    (println (set-contains? s 2))))  ;; 1 (true)

Borrowing (Ownership)

(defn use-buf [^buf data]
  ;; immutable borrow
  (println (count data)))

(defn mutate-buf [^mut buf data]
  ;; mutable borrow
  (push data 42))

;; Implicit borrow: ^ is optional when passing owned values
(let [v (vector 1 2 3)]
  (use-buf v)           ;; automatic borrow
  (use-buf v))          ;; OK — borrow released after each call

Loading Libraries

(load "lib/core.brs")
(load "lib/math.brs")

(defn main []
  (println (factorial 5))
  (println (range 1 10)))

Lambda Functions

;; Inline anonymous functions
(fn [x] (+ x 1))

;; Lambda with borrow annotation
(fn [^buf data]
  (println (count data)))

;; Lambda as function body
(defn make-adder [n]
  (fn [x] (+ x n)))

Type Checking

$ bars check --types examples/hello.brs
✅ Type inference passed.
  main : i64

Algebraic Data Types

(deftype Option [Some i64] [None])
(deftype Result [Ok i64] [Err i64])

(defn handle [res]
  (match res
    (Ok v) (+ v 1)
    (Err e) (* e -1)))

Конструкторите се разпознават по главна буква. match проверява за exhaustiveness.

FFI — Foreign Function Interface

;; Деклариране на C функция
(extern "putchar" [c i64] -> i64)

(defn main []
  (putchar 65))  ;; отпечатва 'A'

Работи с QBE, Cranelift и LLVM — генерира правилни extern declarations.

---

CLI Reference

Command	Description
bars read <file>	Parse and print AST
bars build <file>	Compile to QBE IR via HIR (stdout)
bars build --backend cranelift <file>	Compile via Cranelift to object file
bars build --backend llvm <file>	Compile via LLVM to object file
bars build --release <file>	Release build with optimizations
bars run <file>	Compile, link, and execute (default QBE)
bars run --backend cranelift <file>	Compile, link, and execute (Cranelift)
bars run --backend llvm <file>	Compile, link, and execute (LLVM)
bars repl	Interactive Cranelift JIT session
bars check <file>	Run ownership analysis
bars check --types <file>	Run type inference
bars build --features llvm-backend	Enable LLVM backend (requires LLVM 14+)

---

Project Structure

.
├── src/              # Compiler source (Rust)
│   ├── reader/       # Lexer + Parser
│   ├── ast/          # AST types
│   ├── macro/        # Macro expansion
│   ├── ownership/    # Ownership checker
│   ├── types/        # Hindley-Milner type inference
│   ├── hir/          # High-level IR (flattened)
│   └── backends/     # QBE + Cranelift + LLVM backends
├── runtime/          # C runtime + Boehm GC
├── lib/              # Standard library (.brs)
├── examples/         # Example programs
├── tests/            # Integration tests
└── docs/             # Documentation

---

Backends

Backend	Mode	Status
QBE HIR	Fast AOT debug/release	✅ Working
Cranelift	JIT / REPL / AOT	✅ Working
LLVM	Optimized release (--release)	✅ Working

---

Standard Library

See lib/ and docs/04-stdlib.md.

• lib/core.brs — numeric helpers, vector helpers, range, or, and
• lib/math.brs — square, cube, gcd, lcm, factorial, fib, sum, product
• lib/vector.brs — last, rest, take, drop, reverse, contains?, index-of
• lib/string.brs — str-empty?, str-count
• lib/map.brs — map-empty?, map-has?
• lib/adt.brs — Option, Result типове с helper функции
• lib/test.brs — assert макрос за тестове

Built-in Runtime Functions

Функция	Описание
sqrt n	Корен квадратен
pow base exp	Степенуване
abs n	Абсолютна стойност
str-count s	Дължина на низ
str-concat a b	Конкатенация на низове
slurp path	Прочита файл като низ
spit path content	Записва низ във файл

---

Architecture

.brs → Reader → AST → Macro Expansion → Ownership Check → HIR → Backend → Native Code
                                                                    ├── QBE IR → qbe → cc
                                                                    ├── Cranelift → cc
                                                                    └── LLVM IR → llc → cc

---

Development Status

See ROADMAP.md for the full plan.

Feature	Status
Reader (Lexer + Parser)	✅
AST → HIR → QBE IR	✅
Functions & recursion	✅
Ownership checker	✅
Runtime + Boehm GC	✅
REPL + Cranelift JIT	✅
Built-in macros (when, unless, cond, ->, ->>)	✅
loop / recur	✅
load system	✅
Stdlib	✅
LLVM backend	✅
User-defined macros (defmacro)	✅
Type inference (check --types)	✅
Lambda functions (fn [x] body)	✅
Nested collections	✅
Sets	✅
Cranelift AOT	✅
Generics (implicit polymorphism)	✅
ADT (deftype, exhaustiveness check)	✅
FFI (extern C functions)	✅

---

License

MIT or Apache-2.0