Ruby will destructure objects that are not arrays, but respond to #to_ary

gistfile1.rb

S=Struct.new(:a,:b)
ss = [S.new(1,2), S.new(3,4)]

p ss.map{|a,b| "#{a} #{b}" }
# => ["#<struct S a=1, b=2> ", "#<struct S a=3, b=4> "]

class S ; def to_ary ; to_a ; end ; end

p ss.map{|a,b| "#{a} #{b}" }
# => ["1 2", "3 4"]

Great trick ! Thanks :) I talked about your trick here : http://stackoverflow.com/a/40998675/2431728 ;)