Module: Pacer::Transform::Map

Defined in:
lib/pacer/transform/map.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#block ⇒ Object

Returns the value of attribute block.



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# File 'lib/pacer/transform/map.rb', line 12

def block
  @block
end

Instance Method Details

#help(section = nil) ⇒ Object 



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# File 'lib/pacer/transform/map.rb', line 14

def help(section = nil)
  case section
  when nil
    puts "Works much like Ruby's built-in map method but has some extra options and,\nlike all routes, does not evaluate immediately (see the :routes help topic).\n\nExample:\n\n  mapped = [1,2,3].to_route.map { |n| n + 1 }   #=> #<Obj -> Obj-Map>\n\n  mapped.to_a                                   #=> [2,3,4]\n  mapped.limit(1).to_a                          #=> [2]\n\nNote that the block will be called *twice* in the above example where limit(1)\nis applied to the route after the map is defined. Routes do some pre-processing\nand you can not assume that a function executed within a route will be executed\nthe expected number of times without carefully testing your logic.\n\nFurther, note that routes may be re-executed multiple times:\n\n  [mapped.to_a, mapped.to_a]                    #=> [[2,3,4], [2,3,4]]\n\nThe element_type option is frequently useful. The following looks up elements\nby ID in the graph and produces a fully-fledged vertices route:\n\n  route = [1,2,3].to_route\n  mapped = route.map(graph: g, element_type: :vertex) { |n| g.vertex(n) }\n\n  mapped.out_e                                  #=> #<Obj -> V-Map -> outE>\n  mapped.in_e                                   #=> #<Obj -> V-Map -> inE>\n\nIf you want to map over a route immediately without adding a map step to it,\nuse the synonym for #map built-in to Ruby: #collect\n\n  [1,2,3].to_route.collect { |n| n + 1 }        #=> [2,3,4]\n\n"
  else
    super
  end
  description
end