Racket

Racket is a popular variant of the Scheme programming language. Its features and benefits include:

• Grow your Program:
  Racket's interactive mode encourages experimentation, and quick scripts easily compose into larger systems. Small scripts and large systems both benefit from native-code JIT compilation. When a system gets too big to keep in your head, you can add static types.
• Grow your Language:
  Extend Racket whenever you need to. Mold it to better suit your tasks without sacrificing interoperability with existing libraries and without having to modify the tool chain. When less is more, you can remove parts of a language or start over and build a new one.
• Grow your Skills:
  Whether you're just starting out, want to know more about programming language applications or models, looking to expand your horizons, or ready to dive into research, Racket can help you become a better programmer and system builder.

• The major innovation concerns local recursive variable definitions. Instead of initializing variables with an `undefined' value, Racket raises an exception when such a variable is used before its definition.
• Access the complete release notes.