Install, generate, and decide.

Start with the compatible racc surface, then opt into extended grammar features only when the task calls for them.

Install

gem install ibex
# or
bundle add ibex

Use ibex-runtime when an application only needs to run generated parsers.

ibex -o calculator.rb calculator.y
ruby calculator.rb

The complete guide includes a working calculator grammar and lexer.

Keep default mode for racc migration. Add pragma extended for EBNF, imports, generated lexers, trees, or types.