Parslet is a small Ruby library for constructing parsers in the PEG (Parsing
Expression Grammar) fashion.

Parslet makes developing complex parsers easy. It does so by
- providing the best error reporting possible
- not generating reams of code for you to debug

Parslet takes the long way around to make your job easier. It allows for
incremental language construction. Often, you start out small, implementing the
atoms of your language first; parslet takes pride in making this possible.

WWW: https://kschiess.github.io/parslet/