From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-11-20T20:59:51+09:00
Subject: [ruby-dev:46555] [ruby-trunk - Feature #5550][Rejected] Hash#depth, Hash#flat_length for recursive hashes


Issue #5550 has been updated by mame (Yusuke Endoh).

Status changed from Feedback to Rejected

No feedback, looks hopeless to me.  Closing.

-- 
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Feature #5550: Hash#depth, Hash#flat_length for recursive hashes
https://bugs.ruby-lang.org/issues/5550#change-33202

Author: sawa (Tsuyoshi Sawada)
Status: Rejected
Priority: Normal
Assignee: 
Category: 
Target version: 


I often have a hash whose value is recursively a hash, which may look like the following:

    {"Japan" =>
        {"Hokkaido" => "Sapporo", ...},
        {"Honhuu" =>
            {"Aomori" => "Hirosaki", ...},
            {"Akita" => ...},
            ...
        },
        {"Shikoku" => ...},
        ...
    }

In these cases, it will be convenient if there is a way to know the (maximum) depth of he original hash, and the numbers of all the "terminal nodes". I would like to propose two methods Hash#depth and Hash#flat_length, whose Ruby implementation can be as follows:

    class Hash
	def depth
		1 + (values.map{|v| Hash === v ? v.depth : 1}.max)
	end
	def flat_length
		values.inject(0){|sum, v| sum + (Hash === v ? v.flat_length : 1)}
	end
    end


-- 
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