Module: Nuggets::Hash::NestMixin

Included in:
Hash
Defined in:
lib/nuggets/hash/nest_mixin.rb

Instance Method Summary collapse

Instance Method Details

#array(depth = 0) ⇒ Object

call-seq:

Hash.array([depth]) => aHash

Creates a nested hash, depth levels deep, that yields arrays at the last level.

Example:

hash = Hash.array(2)
hash[:foo][:bar][:a] << 1 << 2
hash[:foo][:bar][:b] << 3 << 4
hash
#=> {:foo=>{:bar=>{:a=>[1, 2], :b=>[3, 4]}}}



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# File 'lib/nuggets/hash/nest_mixin.rb', line 106

def array(depth = 0)
  nest(depth) { [] }
end

#identity(depth = 0) ⇒ Object

call-seq:

Hash.identity([depth]) => aHash

Creates a nested hash, depth levels deep, that yields the keys themselves at the last level.

Example:

hash = Hash.identity(2)
hash[:foo][:bar][:a] #=> :a
hash[:foo][:bar][:b] #=> :b
hash
#=> {:foo=>{:bar=>{:a=>:a, :b=>:b}}}



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# File 'lib/nuggets/hash/nest_mixin.rb', line 89

def identity(depth = 0)
  nest(depth) { |key| key }
end

#nest(depth = 0, value = default = true) ⇒ Object

call-seq:

Hash.nest([depth]) => aHash
Hash.nest([depth[, value]]) => aHash
Hash.nest([depth]) { |key| ... } => aHash

Creates a nested hash, depth levels deep. The final hash will receive a default value of value or, if value is not given but a block is given, the result of the key yielded to that block, or, otherwise, the hash’s original default value, typically nil.

NOTE: If you set the default value for one of the nested hashes explicitly, all of the effects described here disappear for that hash because that also means that the default proc will be cleared.

Example:

hash = Hash.nest(2)
hash[:foo][:bar][:a] = { :x => 1, :y => 2 }
hash[:foo][:bar][:b] = { :x => 0, :y => 3 }
hash
#=> {:foo=>{:bar=>{:b=>{:y=>3, :x=>0}, :a=>{:y=>2, :x=>1}}}}



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# File 'lib/nuggets/hash/nest_mixin.rb', line 52

def nest(depth = 0, value = default = true)
  if depth.zero?
    if default
      if block_given?
        new { |hash, key| hash[key] = yield(key) }
      else
        new { |hash, key| hash[key] = hash.default }
      end
    else
      new { |hash, key| hash[key] = value }
    end
  else
    if default
      if block_given?
        new { |hash, key| hash[key] = nest(depth - 1, &::Proc.new) }
      else
        new { |hash, key| hash[key] = nest(depth - 1) }
      end
    else
      new { |hash, key| hash[key] = nest(depth - 1, value) }
    end
  end
end