Class: Enumerator::Lazy

Inherits:
Enumerator show all
Defined in:
mrbgems/mruby-enum-lazy/mrblib/lazy.rb

Overview

== Acknowledgements

Based on https://github.com/yhara/enumerable-lazy Inspired by https://github.com/antimon2/enumerable_lz http://jp.rubyist.net/magazine/?0034-Enumerable_lz (ja)

Constant Summary

Constants included from Enumerable

Enumerable::NONE

Instance Method Summary collapse

Methods inherited from Enumerator

#each, #each_with_index, #feed, #initialize_copy, #inspect, #next, #next_values, #peek, #peek_values, #rewind, #with_index, #with_object

Methods included from Enumerable

#all?, #any?, #count, #cycle, #detect, #each_cons, #each_slice, #each_with_index, #each_with_object, #entries, #find_index, #first, #group_by, #hash, #include?, #inject, #lazy, #max, #max_by, #min, #min_by, #minmax, #minmax_by, #none?, #one?, #partition, #reverse_each, #sort, #sort_by, #to_h, to_h

Constructor Details

#initialize(obj, &block) ⇒ Lazy

Returns a new instance of Lazy


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 30

def initialize(obj, &block)
  super(){|yielder|
    begin
      obj.each{|x|
        if block
          block.call(yielder, x)
        else
          yielder << x
        end
      }
    rescue StopIteration
    end
  }
end

Instance Method Details

#drop(n) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 89

def drop(n)
  dropped = 0
  Lazy.new(self){|yielder, val|
    if dropped < n
      dropped += 1
    else
      yielder << val
    end
  }
end

#drop_while(&block) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 100

def drop_while(&block)
  dropping = true
  Lazy.new(self){|yielder, val|
    if dropping
      if not block.call(val)
        yielder << val
        dropping = false
      end
    else
      yielder << val
    end
  }
end

#flat_map(&block) ⇒ Object Also known as: collect_concat


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 138

def flat_map(&block)
  Lazy.new(self){|yielder, val|
    ary = block.call(val)
    # TODO: check ary is an Array
    ary.each{|x|
      yielder << x
    }
  }
end

#grep(pattern) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 81

def grep(pattern)
  Lazy.new(self){|yielder, val|
    if pattern === val
      yielder << val
    end
  }
end

#map(&block) ⇒ Object Also known as: collect


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 57

def map(&block)
  Lazy.new(self){|yielder, val|
    yielder << block.call(val)
  }
end

#reject(&block) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 73

def reject(&block)
  Lazy.new(self){|yielder, val|
    unless block.call(val)
      yielder << val
    end
  }
end

#select(&block) ⇒ Object Also known as: find_all


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 64

def select(&block)
  Lazy.new(self){|yielder, val|
    if block.call(val)
      yielder << val
    end
  }
end

#take(n) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 114

def take(n)
  if n == 0
    return Lazy.new(self){raise StopIteration}
  end
  taken = 0
  Lazy.new(self){|yielder, val|
    yielder << val
    taken += 1
    if taken >= n
      raise StopIteration
    end
  }
end

#take_while(&block) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 128

def take_while(&block)
  Lazy.new(self){|yielder, val|
    if block.call(val)
      yielder << val
    else
      raise StopIteration
    end
  }
end

#to_enum(meth = :each, *args, &block) ⇒ Object Also known as: enum_for


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 45

def to_enum(meth=:each, *args, &block)
  unless self.respond_to?(meth)
    raise NoMethodError, "undefined method #{meth}"
  end
  lz = Lazy.new(self, &block)
  lz.obj = self
  lz.meth = meth
  lz.args = args
  lz
end

#uniq(&block) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 161

def uniq(&block)
  hash = {}
  Lazy.new(self){|yielder, val|
    if block
      v = block.call(val)
    else
      v = val
    end
    unless hash.include?(v)
      yielder << val
      hash[v] = val
    end
  }
end

#zip(*args, &block) ⇒ Object


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# File 'mrbgems/mruby-enum-lazy/mrblib/lazy.rb', line 149

def zip(*args, &block)
  enums = [self] + args
  Lazy.new(self){|yielder, val|
    ary = enums.map{|e| e.next}
    if block
      yielder << block.call(ary)
    else
      yielder << ary
    end
  }
end