Convert one object to another

ruby-talk
1

I have two objects, big and little. I need to convert big to little. Big and
little don't have much in common except little's instance variables are a
subset of big's. That is, to convert big to little I need to copy the
instance variables they have in common. What's the right way to do this?
Should I add a "to_little" instance method to big's class, or should I add
a "from_big" singleton method to little's class? Neither one seems right.

2

Tim Hunter wrote:

I have two objects, big and little. I need to convert big to little. Big and
little don't have much in common except little's instance variables are a
subset of big's. That is, to convert big to little I need to copy the
instance variables they have in common. What's the right way to do this?
Should I add a "to_little" instance method to big's class, or should I add
a "from_big" singleton method to little's class? Neither one seems right.

You could do both (TIMTOWTDI) but I would lean towards to_little. It matches the existing Ruby library. For example the to_s() methods, or the String object's to_i() method. I think there are also to_a() for converting to arrays in some objects.

Just my 2 cents,

Eric

3

"Eric Anderson" <eric@afaik.us> schrieb im Newsbeitrag
news:32og2lF3olcvuU1@individual.net...

Tim Hunter wrote:
> I have two objects, big and little. I need to convert big to little.

Big and

> little don't have much in common except little's instance variables

are a

> subset of big's. That is, to convert big to little I need to copy the
> instance variables they have in common. What's the right way to do

this?

> Should I add a "to_little" instance method to big's class, or should I

add

> a "from_big" singleton method to little's class? Neither one seems

right.

You could do both (TIMTOWTDI) but I would lean towards to_little. It
matches the existing Ruby library. For example the to_s() methods, or
the String object's to_i() method. I think there are also to_a() for
converting to arrays in some objects.

Just my 2 cents,

+1 for to_little. Could look like this

class Little
end

class Big
  def to_little
    little = Little.allocate

    %w{@inst_var1 @inst_var2}.each do |iv|
      little.instance_variable_set(iv, instance_variable_get(iv))
    end

    little
  end
end

Kind regards

    robert

4

Robert Klemme wrote:

+1 for to_little. Could look like this

That's the approach I had in mind. Thanks for validating it!