Termflow

A Haskell library for structural, interactive, and collapsible CLI applications.

Termflow transforms your command-line output from a linear stream of text into a structured, real-time interface. Inspired by the logging experience of modern frontend tools, it treats logs as an "event stream" that can be grouped, collapsed, and updated in place.

Features

• 📂 Collapsible Log Streams: Automatically collapses completed task groups while keeping the current activity in focus.
• 🌲 Structured Grouping: Organize logs into hierarchical groups (e.g., "Setup Environment", "Downloading").
• ✨ Rich Styling: Built-in support for colors, bold text, and string composition.
• 🔄 Dynamic Progress: Support for transient progress messages that don't clutter history.
• 🔌 Backend Agnostic:
  • Terminal: Uses ANSI escape codes for folding and in-place updates on TTYs.
  • Plain Text: Automatically degrades to linear output for pipes and CI environments.

Installation

Add termflow to your package.yaml or .cabal file dependencies:

dependencies:
  - termflow

Usage

Here represents a simple example showing how to create a hierarchical flow with Termflow:

{-# LANGUAGE OverloadedStrings #-}

module Main where

import Control.Concurrent (threadDelay)
import Control.Monad.IO.Class (liftIO)
import Termflow

main :: IO ()
main = runFlow $ do
  info $ green "Initializing Termflow..."

  group (bold "Setup Environment") $ do
    info "Creating directories..."
    liftIO $ threadDelay 500000 -- Simulate work

    group (cyan "Downloading dependencies") $ do
      info "Fetching core-lib..."
      liftIO $ threadDelay 500000
      info "Fetching extra-lib..."

    info "Setup complete."

  info $ bold $ green "Done!"

Running the demo

To see Termflow in action in this repository:

stack build
stack exec termflow-exe

Roadmap

• Interactive TUI Components: Support for user input is currently in the design phase.
  • Select (Single item selection)
  • MultiSelect (Multiple item selection)
  • Text Input (String input with validation)
  • Confirm (Yes/No prompts)
• Progress Bars: Support for determinate progress bars (e.g., download percentage).

License

This project is licensed under the BSD-3-Clause License.