Forgive me, for I have done bad things to Ruby again. Credits to @philferne on Twitter for pointing out this might work

pattern_match_string_interpolation.rb

RANKS        = [*2..10, *%w(J Q K A)].map(&:to_s).freeze
RANKS_SCORES = RANKS.each_with_index.to_h

Card = Struct.new(:suit, :rank)

straight = [Card['H', RANKS.first], *RANKS[1..4].map { Card['S', _1] }]
not_straight = [Card['H', RANKS.last], *RANKS[1..4].map { Card['S', _1] }]

def add_rank(r, n) = RANKS[RANKS_SCORES[r] + n]

def straight?(hand)
  hand in [
    Card[*, r],
    Card[*, "#{add_rank(r, 1)}"],
    Card[*, "#{add_rank(r, 2)}"],
    Card[*, "#{add_rank(r, 3)}"],
    Card[*, "#{add_rank(r, 4)}"],
  ]
end

straight?(straight)
# => true

straight?(not_straight)
# => false