— Apr 08, 2016

TL;DR You can use Ruby destructuring and the splat operator (*) to simulate basic pattern matching.

You can do this when assigning variables:

first, *, last = [1,2,3,4]
puts first, last
# 1
# 4

You can do this with procs and lambdas:

foo = ->(_, (first, * last), _) { puts first, last }
foo.call(1, [2,3,4], 5)
# 2
# 4

And you can do this with methods:

def foo(_, (first, *, last), _)
  puts first, last
end
foo(1, [2,3,4], 5)
# 2
# 4

Neat!