lightformat

LightFormat is a lightweight, human-readable data-interchange format designed for configuration files and simple data exchange. It aims to combine readability with a compact encoding and predictable parsing, making it a practical alternative to more verbose formats for everyday use.

The syntax of LightFormat centers on simple indentation-based structure. A value can be a string, number, boolean, or null. Objects map keys to values using a colon separator, for example, key: value. Lists are sequences indicated by lines starting with a dash, such as - item. Strings may be unquoted if they contain only basic characters; quotes are used when needed. Comments are allowed and start with a leading hash character (#) and continue to the end of the line.

LightFormat emphasizes a small, well-defined grammar with no advanced features such as anchors, aliases, or complex references. This minimalist design supports deterministic parsing and straightforward mapping to native language data structures such as dictionaries and lists. The format is amenable to streaming parsers, enabling efficient handling of large configuration files or data payloads.

History and usage of LightFormat trace its origins to a community-driven effort in the early 2020s to provide a simpler alternative to YAML and JSON for configuration and lightweight data exchange. Implementations have appeared in multiple programming languages, and the format is used in projects where readability and small footprint are valued. While not as feature-rich as some alternatives, LightFormat offers a practical balance between human readability and machine parsability for many everyday tasks.

Limitations and considerations include a more constrained feature set compared with JSON or YAML and varying library support across ecosystems. Users should assess toolchain compatibility and validation needs when adopting LightFormat for a project.