COMTHemmer

COMTHemmer is an open-source software framework designed to manage and apply themes to command-line interfaces and text-based user interfaces. It provides a modular system for defining visual styles for commands, prompts, and output, enabling a consistent appearance across programs and environments.

The project originated in 2016 with the aim of standardizing CLI theming. It was developed by a community of volunteers and released publicly in 2017 under the MIT license. Since then it has seen contributions from developers across multiple platforms and is hosted on a central repository, where themes and plugins are shared.

Architecture and components: COMTHemmer consists of a runtime engine, a collection of theme packs, and a theming language. Theme packs describe colors, typography, and layout rules and are authored in a JSON-based schema or in a higher-level domain-specific language. The engine can be integrated into new or existing CLI applications and supports multiple terminal emulators and color schemes, including 16-color, 256-color, and true color environments.

Features include runtime theme switching, live theme reload during development, accessibility options such as improved contrast and scalable font sizing, and an extensible plugin system for input prompts and status bars. It provides a compact API for querying terminal capabilities and adapting output accordingly, plus tools for validating and packaging themes for distribution.

Usage and impact: COMTHemmer has been adopted by several open-source CLI tools and dashboards to provide customizable appearances. It is praised for extensibility and cross-platform consistency, though some users note a learning curve for the theming language and potential performance considerations for large theme sets.

Related concepts include terminal theming, CLI UI libraries, and style specifications for consoles.