Ruby-native
Use familiar classes, constants, and actions. There is no separate lexer language to learn.
Lexer generation, in Ruby
Write the rules.
Know what wins.
flexr keeps lexer specifications in the language they serve. Define readable rules, inspect every decision, then generate deterministic Ruby for deployment.
One input, four decisions
A match you can read.
source
if total == 42 - ifIF
- totalIDENT
- ==EQ
- 42INTEGER
/==/ wins over /=/ because the longest match wins.
Why flexr
One specification, from first test to release.
Explainable
Longest match wins. Source order resolves ties. Unsupported patterns surface early.
Ready both ways
Runtime mode keeps iteration quick. Generated mode keeps deployment reproducible.
Ready when you are
Start with one Ruby file.
gem install flexr Read the quick start