Faking constants with methods

Ruby
1

Hi.

I was wondering why this wouldn’t work:

class Bar
end

class Foo
def initialize
# doesn’t call the method, but gives me the class instead.
p Bar.inspect
end

def Bar
  "whatever"
end

end

I know this is bad style anyway, but would be kind of convenient in
rails controllers:

def ProfileField
ProfileField.for_user(current_user) # for_user being a scope
end

somewhere else in controller:

ProfileField.find(:all)

Anyone got an idea how to “fake” constants that way?

2

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Am 15.11.2010 10:21, schrieb niklas | brueckenschlaeger:

Anyone got an idea how to “fake” constants that way?

Maybe with const_missing?
http://www.ruby-doc.org/ruby-1.9/classes/Module.html#M000928

class Foo

def self.const_missing(sym)
“You wanted to know #{sym}, but it doesn’t exist!”
end

end

puts Foo::ABC #=> You wanted to know ABC, but it doesn’t exist!
puts Foo::Bar #=> You wanted to know Bar, but it doesn’t exist!

Vale,
Marvin
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3

Thank you, but that would only work if the constant isn’t defined. Maybe
I wasn’t being clear: I want to override a constant within an object
with a method.

class Bar
end

class Foo
def Bar
end

def some_method
  Bar.something # this resolves to constant Bar, not method Bar
end

end

4

Well, if I were to change the code that uses the constant, I would
change it to a less ambiguous method call. My point is that I want to
keep the rest of the code as is, hiding the fact that it’s something
else.
But I guess I’ll just leave it and stop investigating on how to write
surprisingly bad code…

5

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Am 15.11.2010 11:02, schrieb niklas | brueckenschlaeger:

def some_method
  Bar.something # this resolves to constant Bar, not method Bar
end

end

That should be possible with #send:

class Bar
end

class Foo
def Bar
end

def some_method
self.send(:Bar).something
end
end

Not nice to read, but works. But I’m not sure if that meets your
original intention of a convenient method to do it…

Vale,
Marvin
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