Turning symbols into class names

Long time no see!

Hopefully I can get some insight into something I’m dealing with, as I
have in the past!

I’m working on something in Rails, however, I believe this to be more
of a Ruby question than anything having to do with Rails.

I’m grabbing all the associations from a Class, and then putting those
associations into an Array. What I get back is an Array of symbols.

Now, I need to do the same thing for those symbols… however, I need
to somehow get Ruby to recognize those symbols as Classes.

So, let’s say in my array, I have a symbol by the name of :foos, that /
should/ correspond with the Foo class.

So…

array looks like: [:foos, :bars]

I need to be able to do something along the lines of:

array[0].to_s.capitalize.singularize.my_method_to_grab_associations

Well, obviously that will give me Foo, but it thinks Foo is a string.

Which leads me to my question -
How do I get my method to give me back what I’m looking for on Foo,
rather than complaining that Foo is a string?

Thanks in advance!

Which leads me to my question -
How do I get my method to give me back what I’m looking for on Foo,
rather than complaining that Foo is a string?

Thanks in advance!

I believe you’re looking for Module#const_get.

Regards,

Gordon

const_get?

Kernel.const_get(:Foo).methods

Hope that helps

Regards,
Lee

Gordon T. wrote:

Regards,

Gordon

Damnit, you were too quick :stuck_out_tongue:

On Dec 12, 4:26 pm, Sebastian H. [email protected]
wrote:

Samantha wrote:

Now, I need to do the same thing for those symbols… however, I need
to somehow get Ruby to recognize those symbols as Classes.

Nitpick: You need ruby to give you the class with a certain name. You don’t
need ruby to “recognize” the symbols as something they’re not.

Semantics, semantics, semantics. :slight_smile:

Well, obviously that will give me Foo, but it thinks Foo is a string.

You make it sound as if ruby was wrong in thinking so. “Foo” is a string.

Oh, I know that “Foo” is a string. I just needed a way to turn that
string into something else. :slight_smile: Of course if anyone is wrong, it’s me,
and not Ruby - I’ve just been working on something for a long amount
of time which has my ‘grr’ factor raised a lil bit. :slight_smile:

Which leads me to my question -
How do I get my method to give me back what I’m looking for on Foo,
rather than complaining that Foo is a string?

By passing the string to const_get, which will return the value of the
constant with the name “Foo” and then calling your methods on that value
(which will be the class object if Foo is a class).
[:foos, :bars].map {|name| Object.const_get(name.to_s.capitalize.singularize)}
should return [Foo, Bar], Foo and Bar being class objects.

Thank you, Sebastian! That did exactly what I needed, which is why
after banging my head incessantly on this for a while now, I decided
to come here - where those who know much, much more than I, reside.

-Samantha

Samantha wrote:

Now, I need to do the same thing for those symbols… however, I need
to somehow get Ruby to recognize those symbols as Classes.

Nitpick: You need ruby to give you the class with a certain name. You
don’t
need ruby to “recognize” the symbols as something they’re not.

Well, obviously that will give me Foo, but it thinks Foo is a string.

You make it sound as if ruby was wrong in thinking so. “Foo” is a
string.

Which leads me to my question -
How do I get my method to give me back what I’m looking for on Foo,
rather than complaining that Foo is a string?

By passing the string to const_get, which will return the value of the
constant with the name “Foo” and then calling your methods on that value
(which will be the class object if Foo is a class).
[:foos, :bars].map {|name|
Object.const_get(name.to_s.capitalize.singularize)}
should return [Foo, Bar], Foo and Bar being class objects.

HTH,
Sebastian

Oops, that needs to be:

:foo.to_s.capitalize.constantize -> Foo

Rails has something even easier:

:foo.to_s.constantize -> Foo

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