lib/dm-core/support/ext/module.rb
module DataMapper; module Ext
module Module
# @api semipublic
def self.find_const(mod, const_name)
if const_name[0..1] == '::'
DataMapper::Ext::Object.full_const_get(const_name[2..-1])
else
nested_const_lookup(mod, const_name)
end
end
private
# Doesn't do any caching since constants can change with remove_const
def self.nested_const_lookup(mod, const_name)
unless mod.equal?(::Object)
constants = []
mod.name.split('::').each do |part|
const = constants.last || ::Object
constants << const.const_get(part)
end
parts = const_name.split('::')
# from most to least specific constant, use each as a base and try
# to find a constant with the name const_name within them
constants.reverse_each do |const|
# return the nested constant if available
return const if parts.all? do |part|
const = if RUBY_VERSION >= '1.9.0'
const.const_defined?(part, false) ? const.const_get(part, false) : nil
else
const.const_defined?(part) ? const.const_get(part) : nil
end
end
end
end
# no relative constant found, fallback to an absolute lookup and
# use const_missing if not found
DataMapper::Ext::Object.full_const_get(const_name)
end
end
end; end