contrafact-rs

A trait for highly composable constraints ("facts") which can be used both to verify data and to generate arbitrary data within those constraints

TODO

• write readme
• add Fact::label method
• add ability to short-circuit a failing Check
• consider using lens-rs for optics instead of closures over mut refs
  • this would enable use of immutable data,
  • which would enable things like prisms which construct a value that's derivable from, but not explicitly present in all, variants of an enum