hledger is a cross-platform plain text accounting application that provides three user interfaces: a command-line tool (hledger), a terminal UI (hledger-ui), and a web UI (hledger-web). It implements double-entry bookkeeping with support for multiple currencies, investment lot tracking, budgeting, forecasting, and CSV import. Users maintain their financial data in human-readable journal files, and hledger generates reports such as balance sheets, income statements, cash flow, and transaction registers. The project is structured as a Haskell monolith with four packages: hledger-lib (core library for parsing, data models, reporting, and output), hledger (CLI with 30+ commands), hledger-ui (terminal interface using brick/vty), and hledger-web (web interface using Yesod). The core library handles reading multiple input formats (journal, CSV, timedot, timeclock), applying queries and filters, and writing reports in text, CSV, JSON, HTML, and ODS formats. The CSV import system uses a declarative rules engine for mapping external data to journal entries. The codebase demonstrates high craftsmanship with clean abstractions, extensive test coverage (unit tests, shell tests, browser-based Playwright tests), and active maintenance with CI/CD across Linux, macOS, and Windows. It has comprehensive documentation, internationalization support, and a well-defined contribution process. While the project has some technical drift (vendored old web dependencies, multiple build systems), it remains a robust and well-engineered application with several reusable components that could be extracted for other projects.
Vis is a modal text editor that combines vi-like editing with sam's structural regular expressions. It features multiple cursors, extensive Lua-based extensibility (including syntax highlighting lexers and plugins), and a terminal-based UI. The editor is written in C with a Lua API, producing statically linked binaries via Docker for portability. Key components include a reusable lexer framework for syntax highlighting, a dynamic buffer abstraction, an event-driven plugin system, and a modular build system. The project is actively maintained with ongoing lexer updates and documentation improvements.