Class: Lens

Inherits:
Object
  • Object
show all
Includes:
NullableOptic
Defined in:
lib/ruby-optics/lens.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from NullableOptic

#nullable

Constructor Details

#initialize(getter, setter) ⇒ Lens

Returns a new instance of Lens.



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# File 'lib/ruby-optics/lens.rb', line 11

def initialize(getter, setter)
  @getter = getter
  @setter = setter
end

Instance Attribute Details

#getter ⇒ Object (readonly)

Returns the value of attribute getter.



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# File 'lib/ruby-optics/lens.rb', line 6

def getter
  @getter
end

#setter ⇒ Object (readonly)

Returns the value of attribute setter.



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# File 'lib/ruby-optics/lens.rb', line 7

def setter
  @setter
end

Class Method Details

.identity ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 50

def self.identity
  @_identity ||= Lens.new(
    -> (obj) { obj },
    -> (new_val, _obj) { new_val }
  )
end

Instance Method Details

#compose_lens(other_lense) ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 31

def compose_lens(other_lense)
  Lens.new(
    -> (obj) { other_lense.getter.(getter.(obj)) },
    -> (new_val, obj) {
      setter.(
        other_lense.setter.(
          new_val,
          getter.(obj)
        ),
        obj
      )
    }
  )
end

#each_lens ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 46

def each_lens
  Each.new(outer_focus = self)
end

#get(obj) ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 16

def get(obj)
  getter.(obj)
end

#modify(obj, &blk) ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 24

def modify(obj, &blk)
  setter.(
    blk.(getter.(obj)),
    obj
  )
end

#set(new_val, obj) ⇒ Object 



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# File 'lib/ruby-optics/lens.rb', line 20

def set(new_val, obj)
  setter.(new_val, obj)
end