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:
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.
<id> 1 </id>
<a> Title </a>
<b> Stuff </b>
<c>
<x-from-other-object>
<x-from-other-object>
....
</c>
And then inherit my data-classes from that simple object: so that (hopefully) I get a mechansim to build up an entire XML doc.
I'm sure I'm re-inventing the wheel here as well...so other tried-and-tested approaches welcome.
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
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