John Doe
10/14/2004 6:34:00 PM
I'm creating a program that allows anonymous plugins to be defined. Since
the user can define their own plugins I want to check that they've defined
them properly. What I can't figure out is how to check the plugin's
correctness without instantiating an instance of it first thus making
checking impossible. I'm sure there is an easy way to do this but I don't
know what it is.
In the example below I want to check that the plugin has defined a
constructor that takes 4 parameters. I seem to only be able to check the
instance. How can I do it?
plugin = Class.new do
def initialize(a,b,c,d)
end
end
instance = plugin.new(0,0,0,0)
def test(object,name,method)
print name," responds to ",method.to_s
if object.respond_to?(method,true)
print " true\n"
print " arity ",object.method(method).arity,"\n"
else
print " false\n"
end
end
test(plugin,"plugin",:new)
test(plugin,"plugin",:initialize)
test(instance,"instance",:new)
test(instance,"instance",:initialize)
## resulting output
plugin responds to new true
arity -1
plugin responds to initialize true
arity -1
instance responds to new false
instance responds to initialize true
arity 4