问题
I would like to create an iterator that I can pass to a method for the method to call.
#!/usr/bin/env ruby
puts "------------------------------------"
puts "1 This works."
puts "------------------------------------"
1.times {|who| puts "Position #{who} works!"}
puts "------------------------------------"
puts "2 This works."
puts "------------------------------------"
aBlock = Proc.new { |who| puts "Position #{who} also works!" }
2.times &aBlock
puts "------------------------------------"
puts "3 This works."
puts "------------------------------------"
def eachIndex
3.times { |i| yield i }
end
eachIndex &aBlock
puts "------------------------------------"
puts "4 This does not work."
puts "------------------------------------"
iterator = lambda { |name| yield name }
iterator.call(4) {|who| puts "Does not work #{who}:-("}
puts "------------------------------------"
puts "5 This does not work."
puts "------------------------------------"
iterator = lambda { |name,&block| yield name }
iterator.call(5) {|who| puts "Does not work #{who}:-("}
puts "------------------------------------"
puts "6 This does not work."
puts "------------------------------------"
iterator = Proc.new { |name,&block| yield name }
iterator.call(6) {|who| puts "Does not work #{who}:-(" }
Can lambda's or proc's be iterators in Ruby? I would like to pass them to a class as a parameter.
回答1:
Here is the way to do it
iterator = -> (name, &block) { block.call name }
iterator.call(4) { |who| puts "It works now #{who} :)" }
P.S. Note i use a shortcut here for a lambda, -> called stabby lambda
来源：https://stackoverflow.com/questions/45571644/in-ruby-can-you-use-the-lambda-or-or-proc-call-method-to-invoke-an-iterator