BernardK

BernardK

Programming Ruby 3.2 (5th Edition): B1.0 page 205, Only then do we create

@noelrappin

page 205, paragraph after the code, line 2 :

then blocks at Ractor.receive. Only then do we create the reading ractor

Because of “Only then” I thought that creating the second Ractor could only take place when the first is waiting on receive. But the trace shows that both Ractors are created, then the blocks are scheduled.

On page 204 (par. 5, code for one, line 1) I liked “Moving down the file”, for a possible replacement of “Only then”.

Having said that, it’s impressive to see the reader sending several times without waiting for a take.

def displayWord(p_word)
    p_word.nil? ? "^nil^" : "|#{p_word}|"
end
    
puts "*** (main) about to create counter"
counter = Ractor.new(name: "counter") do
  puts ">>> ccccc in counter block"
  result = Hash.new(0)
  while (word = Ractor.receive)
    puts "ccccc in counter received word=#{displayWord(word)}"
    result[word] += 1
    puts "ccccc looping"
  end
  puts "ccccc in counter while ended word=#{displayWord(word)}"
  result
end

puts "*** (main) about to create reader"
Ractor.new(counter, name: "reader") do |counter|
  puts ">>> rrrrr in reader block"
  File.foreach("testfile") do |line|
    puts "rrrrr line=#{line}"
    line.scan(/\w+/) do |word|
      puts "rrrrr about to send word=#{displayWord(word)}"
      counter.send(word.downcase)
      puts "rrrrr after send"
    end
  end
  puts "rrrrr about to send nil"
  counter.send(nil)
end

puts "*** (main) about to take counter"
counts = counter.take
counts.keys.sort.each { |k| print "#{k}:#{counts[k]} " }
puts
% ruby -w ractor_word_count_flipped.rb 
*** (main) about to create counter
<internal ... experimental ...
*** (main) about to create reader
*** (main) about to take counter
>>> ccccc in counter block
>>> rrrrr in reader block
rrrrr line=This is line one
rrrrr about to send word=|This|
rrrrr after send
rrrrr about to send word=|is|
rrrrr after send
rrrrr about to send word=|line|
ccccc in counter received word=|this|
...

First Post!

noelrappin

noelrappin

Author of Modern Front-End Development for Rails

Thanks!

Where Next?

Popular Pragmatic Bookshelf topics Top

jimschubert
In Chapter 3, the source for index introduces Config on page 31, followed by more code including tests; Config isn’t introduced until pag...
New
iPaul
page 37 ANTLRInputStream input = new ANTLRInputStream(is); as of ANTLR 4 .8 should be: CharStream stream = CharStreams.fromStream(i...
New
brianokken
Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
New
jamis
The following is cross-posted from the original Ray Tracer Challenge forum, from a post by garfieldnate. I’m cross-posting it so that the...
New
JohnS
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps. With: ruby-3.0.0 s...
New
AleksandrKudashkin
On the page xv there is an instruction to run bin/setup from the main folder. I downloaded the source code today (12/03/21) and can’t see...
New
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
brian-m-ops
#book-python-testing-with-pytest-second-edition Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
rainforest
Hi, I’ve got a question about the implementation of PubSub when using a Phoenix.Socket.Transport behaviour rather than channels. Before ...
New
New

Other popular topics Top

Devtalk
Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:
New
AstonJ
Or looking forward to? :nerd_face:
490 12945 266
New
AstonJ
SpaceVim seems to be gaining in features and popularity and I just wondered how it compares with SpaceMacs in 2020 - anyone have any thou...
New
Rainer
My first contact with Erlang was about 2 years ago when I used RabbitMQ, which is written in Erlang, for my job. This made me curious and...
New
dimitarvp
Small essay with thoughts on macOS vs. Linux: I know @Exadra37 is just waiting around the corner to scream at me “I TOLD YOU SO!!!” but I...
New
AstonJ
Saw this on TikTok of all places! :lol: Anyone heard of them before? Lite:
New
New
PragmaticBookshelf
Author Spotlight: Peter Ullrich @PJUllrich Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
New
PragmaticBookshelf
Get the comprehensive, insider information you need for Rails 8 with the new edition of this award-winning classic. Sam Ruby @rubys ...
New

Sub Categories: