Hash::Wrapper(K, V)

Wraps a Hash object. The including type will behave as a read-only hash, where objects returned by methods will be wrapped as well if the return type is the same as the original hash.

class Table
  include HashWrapper(String, Int32)
end

table = Table.new({"a" => 1, "b" => 2})
table["a"]?                   # => 1
table["b"]?                   # => 2
table["c"]?                   # => nil
table["c"] = 3                # does not compile
table.select { |_, v| v > 2 } # => Table{"b" => 2}