How to Make a Ruby Class act Like a Hash with Setter - ruby

Question

For academic reasons, I'd like to make an instance of Ruby class act like a hash.
GOALS
Initialize MyClass instance with a hash # success
Request values from instance of myClass, like a hash # success
Then set properties as a hash # fail
Although some discussion exists, I tried what's out there (1, 2) with no success. Let me know what I'm doing wrong. Thanks!
class MyClass
attr_accessor :my_hash
def initialize(hash={})
#my_hash = hash
end
def [](key)
my_hash[key]
end
def set_prop(key, value)
myhash[key] = value
end
end
test = myClass.new({:a => 3}) #=> #<MyClass:0x007f96ca943898 #my_hash={:a=>3}>
test[:a] #=> 3
test[:b] = 4 #=> NameError: undefined local variable or method `myhash' for #<MyClass:0x007f96ca9d0ef0 #my_hash={:a=>3}>

Answer 1

You declared set_prop, but you're using []= in tests. Did you mean to get this?
class MyClass
attr_accessor :my_hash
def initialize(hash={})
#my_hash = hash
end
def [](key)
my_hash[key]
end
def []=(key, value)
my_hash[key] = value
end
end
test = MyClass.new({:a => 3}) # success
test[:a] # success
test[:b] = 4 # success
test.my_hash # => {:a=>3, :b=>4}

Answer 2

module HashizeModel
def [](key)
sym_key = to_sym_key(key)
self.instance_variable_get(sym_key)
end
def []=(key, value)
sym_key = to_sym_key(key)
self.instance_variable_set(sym_key, value)
end
private
def to_sym_key(key)
if key.is_a? Symbol
return ('#'+key.to_s).to_sym
else
return ('#'+key.to_s.delete('#')).to_sym
end
end
end

Answer 3

You should write it as test = MyClass.new({:a => 3}) and the below code should work.
class MyClass
attr_accessor :my_hash
def initialize(hash={})
#my_hash = hash
end
def [](key)
#my_hash[key]
end
def []=(key,val)
#my_hash[key]=val
end
def set_prop(key, value)
#myhash[key] = value
end
end
test = MyClass.new({:a => 3})
test[:a]
test[:b]= 4
test.my_hash # => {:a=>3, :b=>4}