Not technically but it can run a lot of Ruby code with no changes.

That is a very, _very_ dubious claim indeed considering that even stuff as trivial as `attr_reader`, `attr_writer` and `attr_accessor` go by a different name in Crystal.

Although I didn't say it was, you're actually half right since its an inspiration of Ruby even when some code compiles 1:1 with Crystal; the same inspiration can be also said for Elixir.

But the benchmarks here don't lie and one can still say that in syntax similarity, Crystal is a 'faster and memory efficient Ruby with static types'.

> one can still say that in syntax similarity, Crystal is a 'faster and memory efficient Ruby with static types'

Actually they don't even share the same syntax for declaring getters and setters. Honestly speaking I think people really only think of Crystal as "faster Ruby with static types" because they've mostly been exposed to C-style languages so anything that doesn't look like C just blurs together as "the same".

(Obviously Crystal is heavily inspired by Ruby, but there's a huge difference between "heavily inspired by" and "an implementation of".)