Nice. What about pushing to leaves which are arrays, or incrementing
leaves which are numbers? If the array leaf didn't exist, or a number
wasn't set yet, << must create an empty array and push the element from
the RHS into it, and += must init the leaf to 0 and add the RHS to it.
Here's the corresponding ruby:
# ruby!
class MagicalExpandingHash < Hash
def initialize(*params)
if params.first.is_a? MagicalExpandingHash
@parentObj, @parentKey = params[0..1]
params = params[2..-1]
end
super(*params) { |h,k|
h[k] = MagicalExpandingHash.new(self,k)
}
end
def <<(elem)
if @[EMAIL PROTECTED]
@[EMAIL PROTECTED] = [ elem ]
else
raise ArgumentError, "Can't push onto populated index", caller
end
end
def +(elem)
unless elem.is_a? Numeric
raise ArgumentError, "Can't add a non-Numeric value", caller
end
if @[EMAIL PROTECTED]
@[EMAIL PROTECTED] = elem
else
raise ArgumentError, "Can't add to populated index", caller
end
end
def to_hash
h = Hash.new
self.each_pair {|k,v| h[k]=(v.class==self.class)? v.to_hash : v }
return h
end
def from_hash(h)
h.each_pair {|k,v| self[k]=(v.is_a? Hash) ?
self.class.new.from_hash(v) : v}
end
def marshal_dump
self.to_hash
end
def marshal_load(h)
from_hash(h)
end
end
# examples
if $0 == __FILE__
meh = MagicalExpandingHash.new
meh['usa']['france'] << 'tocqueville'
meh['usa']['france'] << 'freedom fries'
meh['life']['meaning'] += 42
puts meh.inspect
# => {"usa"=>{"france"=>["tocqueville", "freedom fries"]},
"life"=>{"meaning"=>42}}
end
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