I have a situation where I need to dynamically execute an object from a
String name. I read in pickaxe that as long as a capitalize the class
name in the string, Ruby will see it as a Constant and thusly allow me
to use it.
For example:
module Test
class MyClass
def do_something
puts “Something done.”
end
end
When I execute the above caller code, I get an error saying
undefined method `new’ for “Test::MyClass”:String (NoMethodError)
So, obviously, Ruby is telling me that there is no new method for the
String “Test::MyClass”. I’m trying to instantiate the class this way as
I have specific methods that return object besides String, so I’m
guessing eval(cls) isn’t appropriate for me. Also, I checked the
archives on the list with no luck.
cls = “Test::MyClass”
So, obviously, Ruby is telling me that there is no new method for the
String “Test::MyClass”. I’m trying to instantiate the class this way as
I have specific methods that return object besides String, so I’m
guessing eval(cls) isn’t appropriate for me. Also, I checked the
archives on the list with no luck.
Any suggestions?
Thx,
def klass_stamp(hierachy, *a, &b)
ancestors = hierachy.split(%r/::/)
parent = Object
while((child = ancestors.shift))
klass = parent.const_get child
parent = klass
end
klass::new(*a, &b)
end
class A; class B;end; end
klass_stamp 'A::B'
def klass_stamp(hierachy, *a, &b)
ancestors = hierachy.split(%r/::/)
parent = Object
while((child = ancestors.shift))
klass = parent.const_get child
parent = klass
end
klass::new(*a, &b)
end
class A; class B;end; end
klass_stamp 'A::B'
hth.
-a
Actually, I just found this, which is a little simpler, but looks like
it does the same
mod = Module
name.split(/::/).each {|m| mod = mod.const_get(m) }
m = mod.new
