Nested-Iterators.md

Nested Iterators

Introduction

A Nested Iterator occurs when a block contains another block.

Example

Given

class Duck
  class << self
    def duck_names
      %i!tick trick track!.each do |surname|
        %i!duck!.each do |last_name|
          puts "full name is #{surname} #{last_name}"
        end
      end
    end
  end
end

Reek would report the following warning:

test.rb -- 1 warning:
  [5]:Duck#duck_names contains iterators nested 2 deep (NestedIterators)

Current Support in Reek

Nested Iterators reports failing methods only once. Object#tap is ignored by default and thus does not count as iterator. Furthermore iterators without block arguments are not counted, e.g.:

def foo
  before do
    item.each do |part|
      puts part
    end
  end
end

would not smell of NestedIterators (given a maximum allowed nesting of 1) since the before would not be counted (because it doesn't pass any arguments to the block).

Configuration

Nested Iterators offers the Basic Smell Options, plus:

Option	Value	Effect
max_allowed_nesting	integer	The maximum depth of nested iterators. Defaults to 1
ignore_iterators	Array	List of iterators to be excluded from the smell check. Includes only tap at the moment