Announcing NeoHaskell v0.2.0: Bringing Elm-Inspired Architecture to CLI Apps

We're excited to announce the release of NeoHaskell v0.2.0! This version marks a significant milestone in our journey to create a more accessible and powerful Haskell-based language. With this release, we're introducing a basic scaffolding for CLI applications inspired by Elm's architecture, along with substantial enhancements to our core library.

The Elm-Inspired CLI Architecture

One of the most exciting features in v0.2.0 is the introduction of, an Elm-inspired, event sourcing architecture for building CLI applications. This approach brings the clarity and maintainability of Elm's design to the world of command-line tools.

This architecture allows developers to create CLI apps with a clear separation of concerns, making it easier to reason about application state and user interactions.

Let's look at an example of how to build a simple CLI app:

module SimpleTodo (main) where

import Core
import Command qualified
import Platform qualified

type Model =
  Record
    '[ "todos" := Array Text,
       "currentInput" := Text
     ]

data Message
  = AddTodo
  | UpdateInput Text
  | RemoveTodo Int
  | NoOp
  deriving (Show)

init :: (Model, Command Message)
init =
  let initialModel =
        ANON
          { todos = [],
            currentInput = ""
          }
  in (initialModel, Command.none)

update :: Message -> Model -> (Model, Command Message)
update message model =
  case message of
    AddTodo ->
      if Text.isEmpty model.currentInput
        then (model, Command.none)
        else
          ( model
              { todos = Array.push model.currentInput model.todos,
                currentInput = ""
              },
            Command.none
          )
    UpdateInput newInput ->
      (model {currentInput = newInput}, Command.none)
    RemoveTodo index ->
      ( model {todos = Array.removeAt index model.todos},
        Command.none
      )
    NoOp ->
      (model, Command.none)

view :: Model -> Text
view model = do
  let todoList = Text.joinWith "\n" model.todos
  let header = "Todo List:\n"
  let footer = "\nCurrent input: " ++ model.currentInput
  header ++ todoList ++ footer

main :: IO ()
main = Platform.init (ANON {init = init, view = view, update = update})

This example demonstrates the key components of the Elm-inspired architecture:

1. Model: Represents the application state
2. Message: Defines the possible events in the application
3. init: Sets up the initial model and commands
4. update: Handles state transitions based on messages
5. view: Renders the current state as text
6. main: Initializes the application using the Platform module

Expanded Core Library

We've significantly enhanced our core library to provide more powerful tools for NeoHaskell developers:

• New concurrency primitives: Channel, Var, and ConcurrentVar
• AsyncIO module for handling asynchronous operations
• Extended Array module with useful functions like flatMap and forEach
• Version module for parsing and working with semantic versions
• The Unknown type for handling dynamic typing scenarios
• A Record module for working with extensible records
• New Json and Yaml modules for data serialization
• An OptionsParser module to simplify CLI argument parsing
• A Console module with built-in debugging capabilities

Trait System Enhancements

We've reorganized and expanded our trait system to provide a more cohesive and powerful set of abstractions:

• Improved Appendable, Applicable, and Combinable traits
• A new ToText trait for consistent string conversion across types

Get Involved

We're excited to see what the community builds with NeoHaskell v0.2.0! Here's how you can get started:

1. Check out our GitHub repository for the latest code
2. Join our Discord community to discuss ideas and get help
3. Try building a small CLI app and share your experience

Your feedback and contributions are crucial as we continue to evolve NeoHaskell. Let's work together to create a more accessible and powerful development experience!

Happy coding!

Nick