How to pass a instance/accessor variable in ruby to another class and get data stored in respective variable?

Question

Referring to the below code is there a way that I can pass the variable row from class A to class B#kick and get the data stored?

class A attr_accessor :row def fetch B.new.kick(self.row) puts row.inspect end end class B def kick(x) x = [3,4] end end @test = A.new.fetch expect(@test.row).to eql([3,4])

Current O/P => nil

However If I pass self and assign that works , but I dont want to use this approach: Working Code

class A attr_accessor :row def fetch B.new.kick(self) puts row.inspect end end class B def kick(x) x.row = [3,4] end end @test = A.new.fetch #=> [3, 4]

This is expected because case 1 is a value and case 2 is a reference. You can only access object methods by referencing the object. — Ruby Racer
– Ruby Racer, Commented Mar 4, 2019 at 18:03

Fabio · Accepted Answer · 2019-03-04 18:29:19Z

Short version:
x = [3, 4] will create new instance of array and saves to x variable, where row will still reference to the original value(or no value nil).

Another approach could be the kick method to return "kicked" value.

class A def fetch @row = B.new.kick puts row.inspect end end class B def kick(x) [3,4] end end

If you want to follow object-oriented programming principle "Tell, don't ask" you can try visitor pattern approach.

class A def fetch B.new.kick(self) puts row.inspect end def save(row) @row = row end end class B def kick(x) x.save([3,4]) end end

Yes, this works fine but my use case is something like what if B.new.kick raises an error I will not get any data. My use case is I want to store the data in array in runtime even if kick method raises an exception I have data in it.
@SantoshMohanty, you will not get any data anyway if error will be raised in a kick method.
@SantoshMohanty: if your version of B#kick raises an error, the program will crash just as well.

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