What is "crystal-lang"

Crystal is an object-oriented programming language developed and developed by Ary Borenszweig and Juan Wajnerman and more than two hundred contributors. Crystal is developed as open source software under the Apache 2.0 license version with Ruby-inspired syntax. It is a language compiled with static type checking, but specification of the variable types or arguments of the method is usually not required. Types are solved by an advanced global type inference algorithm. Crystal is in active development phase.