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Hey there, I have read the few posts here on when/how to use the visitor pattern, and some articles/chapters on it, and it makes sense if you are traversing an AST and it is highly structured, and you want to encapsulate the logic into a separate "visitor" object, etc. But with Ruby, it seems like overkill because you could just use blocks to do nearly the same thing. I would like to pretty_print xml using Nokogiri. The author recommended that I use the visitor pattern, which would require I create a FormatVisitor or something similar, so I could just say "node.accept(FormatVisitor.new)". The issue is, what if I want to start customizing all the stuff in the FormatVisitor (say it allows you to specify how nodes are tabbed, how attributes are sorted, how attributes are spaced, etc.). One time I want the nodes to have 1 tab for each nest level, and the attributes to be in any order The next time, I want the nodes to have 2 spaces, and the attributes in alphabetical order The next time, I want them with 3 spaces and with two attributes per line. I have a few options: Create an options hash in the constructor (FormatVisitor.new({:tabs => 2}) Set values after I have constructed the Visitor Subclass the FormatVisitor for each new implementation Or just use blocks, not the visitor Instead of having to construct a FormatVisitor, set values, and pass it to the node.accept method, why not just do this: node.pretty_print do |format| format.tabs = 2 format.sort_attributes_by {...} end That's in contrast to what I feel like the visitor pattern would look like: visitor = Class.new(FormatVisitor) do attr_accessor :format def pretty_print(node) # do something with the text @format.tabs = 2 # two tabs per nest level @format.sort_attributes_by {...} end end.new

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