Awesome
Lasca Language
Lasca is Scala shifted towards Haskell.
Lasca is a LLVM-based statically or dynamically typed strict functional programming language. Simplified OCaml if you will.
It has a 'dynamic' compilation mode, meaning instant code generation without compile time type checking/inference, allowing instant compilation/execution cycle, and more freedom dynamic languages give.
It has a full type inference, parametric polymorphism, GC, algebraic data types, pattern matching, and type classes are coming soon.
Imagine
- Scala with fast compilation/start time, optional dynamic typing, and without null
- Go with ADTs, global type inference, and parametric polymorphism
- Haskell with decent records syntax, runtime polymorphism, and string interpolation
- OCaml with typeclasses, overloaded +-*/ for ints and floats, and do-notation
- Rust with garbage collector without <::>!?
- Erlang with types and fast execution
- Python with multithreading, pattern matching, and multiline lambdas
- TypeScript with indentation significant syntax, and LLVM
- Julia with static type checking, and zero-based indexing
Inspired by:
- Scala
- Haskell, Liquid Haskell, Linear Haskell, Idris
- OCaml/SML/F#/1ML
- Clojure (persisted data structures, HAMT/CHAMP)
- Go (CSP)
- Erlang (actors, immutability, minimalism)
- Python (docstrings, doctests, syntax)
- Julia
- Swift
- Nim
- Pony
- Koka (algebraic effects)
Ideas
- light, non-symbol-polluted syntax (Python)
- indentation-based
- readability first
- fast development cycle
- presentation compiler for IDE integration
- IDE-friendly (intellisence 'dot-autocomplete', auto-formatting, compiler API)
- type-safe
- strict functional
- expression-based
- practical first, but as clean and concise as possible
- prefer things done one way
- LLVM backend
- JavaScript/WebAssembly backend (native or via LLVM/emscripten)
- GraalVM backend?
- no OOP and data subclassing/inheritance?
- syntactic sugar is ok
- no null
- annotations (Java/Python-style)
- annotation-based extensions
- macros based metaprogramming (like Scala Macros, Template Haskell)
- Concurrency Oriented Programming (Erlang). Objects are out. Concurrency is in.
- Gradual Typing
- Deferred Type Errors (runtime compilation mode, Haskell)
- Linear/affine types (Rust, Linear Haskell)?
- Liquid Type system (refinement types, Leon, Liquid Haskell) and Z3/CVC4 as proof assistant.
- Algebraic Subtyping for module system
- import features (Scala-like)
- compile-time and runtime reflection
- save/distribute AST (Scala TASTY). Full program optimization/reflection
- important things must be greppable and googlable, call it searchability :)
- compiler as a service: Language Server Protocol
- markdown/rst comments/docs, doctest (Julia, Python)
- CPS/Actors/π-calculus/STM?, non-blocking IO, reactive
Example
Current implementation uses braces and semicolons, but I consider adding indentation-based syntax, or semicolon inference.
-- Algebraic data type a la Haskell
data JValue
= JNull
| JNum(n: Float)
| JString(s: String)
| JBool(v: Bool)
| JArray(v: [JValue])
| JObject(v: Map String JValue)
-- function argument type annotations are optional, compiler infers those
def jsonToString(js: JValue) = match js {
JObject(m) ->
if Map.isEmpty(m) then "{}" else {
println(toString(m));
res = Array.makeArray(m.size, "");
var idx = 0;
Map.foreachWithKey(m, { k, v ->
setIndex(res, idx.readVar, "\"${k}\": ${jsonToString(v)}");
idx := idx.readVar + 1;
});
s = String.join(", ", res);
"{ ${s} }"
}
JNull -> "null"
JNum(n) -> toString(n)
JBool(v) -> toString(v)
JString(v) -> "\"${v}\""
JArray(v) -> {
values = Array.map(v, jsonToString);
toString(values);
}
}
What Works Right Now
- JIT and AOT compilation and execution (via LLVM OrcJIT)
- lasca -e hello.lasca to execute
- lasca hello.lasca to create a binary
- type inference
- dynamic typing mode (
lasca -e --mode dynamic hello.lasca
) - ADTs, inner functions, out of order function definitions
- pattern matching
- calling external C functions
- string interpolation, UTF8 encoded immutable strings
- builtin types:
String
,Bool
,Int
,Byte
,Int16
,Int32
,Float
,Array
,ByteArray
,Var
,FileHandle
- implemented
List
,Option
,Either
,Map
,ArrayBuffer
- regular expressions with PCRE-2
- overloaded
+
-
*
/
operators
Package System
Consider Nix as package manager
Compiler Modes
- Dynamic Mode, aka Prototype Mode. Syntax is checked. All types are dynamically checked.
- Static Mode. Syntax is checked. Typechecking/inference, faster execution.
- Hardcore Liquid types enabled. (See Liquid Haskell) Proves checked. Array bounds checks eliminated.
Type System
- Hindley-Milner by default, dependent types if needed
- traits, kind of type classes
- Liquid types as in Liquid Haskell
Memory Management
GC, concurrent mark and sweep per actor/green thread GC Consider MultiCore Ocaml GC
for now, use Boehm conservative GC
Other
- indentation significant (i.e. Python, Haskell)
- uppercase Typenames, lowercase idents and type arguments (Haskell/Scala style)
- pattern-matching
- ADT, traits, type classes
- easy C interoperability
- no exceptions (Go/Rust panic style errors)
- don't overuse `'~!@#$%^&* symbols
- default immutability
- string interpolation: "${ident} = ${expression}"
- multiline strings
- Uniform Function Call Syntax (Rust, D). For example, any function can be a method for its first argument:
def toString(s: String) = ...
"Hello".toString
def plus(l: Num, r: Num)
1.plus(2)
- uniform select principle. Use (.) for record field selection, func calls, package name resolution etc
- UTF-8 strings
- Haskell-like application for type functions: Option Int, Either Int String, etc
Install on Mac OS using Homebrew
brew install boehmgc pcre2
brew install nau/lasca/lasca-compiler
Setup LASCAPATH environment variable. Add this to your .bash_profile
export LASCAPATH="$(brew --prefix lasca-compiler)/src"
Try it!
echo 'def main() = println("Hello Lasca!")' > hello.lasca
lasca -e hello.lasca
> Hello Lasca!
Add bash completion config for lasca compiler options:
lasca --bash-completion-script lasca > $(brew --prefix)/etc/bash_completion.d/lasca
Build on Mac OS
You need LLVM 6.0 installed, and latest Haskell Stack.
brew install cmake boehmgc pcre2
brew install llvm-hs/llvm/llvm-6.0 # this compiles llvm from sources, make take some time
brew install haskell-stack
stack setup
Setup LASCAPATH environment variable. Add this to your .bash_profile
export LASCAPATH="${lasca-compiler-src-dir}/libs/base"
Add your ~/.local/bin
directory to your PATH
export PATH=$PATH:~/.local/bin
Build and install lasca compiler
make install
Add bash completion config for lasca compiler options:
lasca --bash-completion-script lasca > $(brew --prefix)/etc/bash_completion.d/lasca
Run hello.lasca
lasca --exec examples/hello.lasca
Build on Ubuntu
Requirements: Haskell Stack > 1.6, Cabal > 2.0, LLVM 6, CMake
Don't install Haskell Stack from apt. It's likely to be older than 1.6 and won't be able to upgrade
Do this instead:
curl -sSL https://get.haskellstack.org/ | sh
sudo apt install llvm-6.0-dev libgc-dev zlib1g-dev cmake
sudo add-apt-repository universe
sudo apt install libpcre2-dev
export LASCAPATH="${lasca-compiler-src-dir}/libs/base"
export PATH=$PATH:~/.local/bin
stack setup
make install
lasca -e examples/hello.lasca
Current n-body run
There are several implementation of n-body problem Currently it's quite slow due to boxing.
$ time lasca -e -O2 examples/nbody.lasca -- 50000000
-0.169075164
-0.169059907
real 7m13.261s
user 7m39.476s
sys 0m38.716s
find src -name "*.hs" | xargs cat | wc -l
4738
cat rts/runtime.c rts/builtin.c rts/lasca.h | wc -l
1324