Class: Hashery::OrderedHash

Inherits:
Hash show all
Defined in:
lib/hashery/ordered_hash.rb

Overview

Note:

As of Ruby 1.9+ this class is not needed, since Ruby 1.9’s standard Hash tracks inseration order.

This implementation derives from the same class in ActiveSupport library.

OrderedHash is a simple ordered hash implmentation, for users of Ruby 1.8.7 or less.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Hash

create, #rekey, #rekey!, #retrieve, #to_stash

Constructor Details

#initialize(*args, &block) ⇒ OrderedHash

Returns a new instance of OrderedHash.



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# File 'lib/hashery/ordered_hash.rb', line 31

def initialize(*args, &block)
  super
  @keys = []
end

Class Method Details

.[](*args) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 36

def self.[](*args)
  ordered_hash = new

  if (args.length == 1 && args.first.is_a?(Array))
    args.first.each do |key_value_pair|
      next unless (key_value_pair.is_a?(Array))
      ordered_hash[key_value_pair[0]] = key_value_pair[1]
    end

    return ordered_hash
  end

  unless (args.size % 2 == 0)
    raise ArgumentError.new("odd number of arguments for Hash")
  end

  args.each_with_index do |val, ind|
    next if (ind % 2 != 0)
    ordered_hash[val] = args[ind + 1]
  end

  ordered_hash
end

Instance Method Details

#[]=(key, value) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 65

def []=(key, value)
  @keys << key unless key?(key)
  super(key, value)
end

#clear ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 124

def clear
  super
  @keys.clear
  self
end

#delete(key) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 70

def delete(key)
  if has_key? key
    index = @keys.index(key)
    @keys.delete_at(index)
  end
  super(key)
end

#delete_if ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 78

def delete_if
  super
  sync_keys!
  self
end

#each ⇒ Object Also known as: each_pair 



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# File 'lib/hashery/ordered_hash.rb', line 118

def each
  @keys.each{ |key| yield(key, self[key]) }
end

#each_key ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 110

def each_key
  @keys.each{ |key| yield(key) }
end

#each_value ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 114

def each_value
  @keys.each{ |key| yield(self[key]) }
end

#initialize_copy(other) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 60

def initialize_copy(other)
  super(other)
  @keys = other.keys
end

#inspect ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 153

def inspect
  "#<OrderedHash #{super}>"
end

#keys ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 94

def keys
  @keys.dup
end

#merge(other_hash) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 141

def merge(other_hash)
  dup.merge!(other_hash)
end

#merge!(other_hash) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 136

def merge!(other_hash)
  other_hash.each{ |k,v| self[k] = v }
  self
end

#reject(&block) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 90

def reject(&block)
  dup.reject!(&block)
end

#reject! ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 84

def reject!
  super
  sync_keys!
  self
end

#replace(other) ⇒ Object

When replacing with another hash, the initial order of our keys must come from the other hash, ordered or not.



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# File 'lib/hashery/ordered_hash.rb', line 147

def replace(other)
  super
  @keys = other.keys
  self
end

#shift ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 130

def shift
  k = @keys.first
  v = delete(k)
  [k, v]
end

#sync_keys! ⇒ Object (private) 



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# File 'lib/hashery/ordered_hash.rb', line 159

def sync_keys!
  @keys.delete_if{ |k| !key?(k) }
end

#to_a ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 106

def to_a
  @keys.map{ |key| [ key, self[key] ] }
end

#to_hash ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 102

def to_hash
  self
end

#to_yaml(opts = {}) ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 18

def to_yaml(opts = {})
  YAML.quick_emit(self, opts) do |out|
    out.seq(taguri, to_yaml_style) do |seq|
      each do |k, v|
        seq.add(k => v)
      end
    end
  end
end

#to_yaml_type ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 14

def to_yaml_type
  "!tag:yaml.org,2002:omap"
end

#values ⇒ Object 



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# File 'lib/hashery/ordered_hash.rb', line 98

def values
  @keys.collect{ |key| self[key] }
end