Ruby: attr_accessor generated methods - how to iterate them (in to_s - custom format)?

Question

I need a Class which has an semi-automatic 'to_s' method (to generate XML in fact). I would like to iterate through all the automatic methods set up in my 'attr_accessor' line: ``` class MyClass attr_accessor :id,:a,:b,:c end c=MyClass.new ``` So far I'm doing a basic: ``` c.methods - Object.methods => ["b", "b=", "c", "c=", "id=", "a", "a="] ``` I am facing a few challenges: - 'id' may cause a slight headache - as Object already seems to have an 'id'. - The 'c.methods' call above, returns Strings - I'm not getting any other meta-data ? (In Java 'method' is an object, where I could perform further reflection). - I have one-to-many relationships I have to deal with ('c' is an array type of other object types). This is what I'm trying to do: I want to design a simple Object which has a 'to_s' which will build up an XML fragment: for instance. ``` 1 Title Stuff

....

``` And then inherit my data-classes from…

Accepted Answer

To get method objects from a string, you can use the methods `method` or `instance_method` (where `method` would be called on an object and `instance_method` on a class). The only interesting information it gives you is arity, though (as opposed to java where it'd also give you the types of the return value and the arguments, which of course isn't possible in ruby).

Your title suggests that you only want to iterate over methods created by `attr_accessor`, but your code will iterate over every method defined in your class, which could become a problem if you wanted to add additional non-accessor methods to your class.

To get rid of that problem and the problem with `id`, you could use your own wrapper around `attr_accessor` which stores which variables it created accessors for, like so:

```
module MyAccessor
  def my_attr_accessor *attrs
    @attrs ||= []
    @attrs << attrs
    attr_accessor *attrs
  end

def attrs
    @attrs
  end
end

class MyClass
  extend MyAccessor
  my_attr_accessor :id,:a,:b,:c

def to_s
    MyClass.attrs.each do |attr|
      do_something_with(attr, send(attr))
    end
  end
end
```

For problem 3 you can just do

```
if item.is_a? Array
  do_something
else
  do_something_else
end
```

Ruby: attr_accessor generated methods - how to iterate them (in to_s - custom format)?

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