#
# Copyright (c) 2006 The Apache Software Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

class Object

  public

  def traverse()
    traverse! {|o| yield(o); o}
  end

  def traverse_children!()
    instance_variables.each {|v|
      value = instance_variable_get(v)
      replacement = yield(value)
      instance_variable_set(v, replacement) unless replacement.equal? value
    }
  end

  def traverse!(replacements = {})
    return replacements[__id__] if replacements.has_key? __id__
    replacement = yield(self)
    replacements[__id__] = replacement
    traverse_children! {|o| o.traverse!(replacements) {|c| yield(c)}}
    return replacement
  end

end

class Array
  def traverse_children!()
    map! {|o| yield(o)}
  end
end

class Hash
  def traverse_children!()
    mods = {}
    each_pair {|k, v|
      key = yield(k)
      value = yield(v)
      mods[key] = value unless key.equal? k and value.equal? v
      delete(k) unless key.equal? k
    }

    merge!(mods)
  end
end