#!/usr/bin/ruby
#
## https://rosettacode.org/wiki/Singly-linked_list/Element_definition
#
var foo_node = Hash.new(foo => 1);
var bar_node = Hash.new(bar => 2);
var node = :(
data => 'say what',
next => foo_node,
);
node{:next} = bar_node; # mutable
say node;