A Ruby DSL and script for the code generation of Objective-C immutable Value Objects that use the Mantle library.
Creating easy-to-use Objective-C Value Objects using the Builder Pattern with immutable Mantle models.
Hamster gives you immutable structures in Ruby; RSchema gives you schemas to shape your data; RSchema-Hamster brings them together seamlessly.
I benchmarked some tests run in JRuby that compare the Hamsterdam library using Hamster's immutable Hashes vs Clojure's PeristentHashMap, plus some gotchas.
Hamsterdam is a Ruby gem that makes it fun and easy to define and use efficient immutable record types in Ruby, backed by Hamster's Hash class.
An example of using Celluloid Actors to provide a poor man's Ref (Clojure-like) around an immutable data structure in JRuby to protect shared state.
How using Hamster's efficient, immutable, thread-safe collections can prevent ConcurrencyError exceptions in JRuby.