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

jimmykiang
This test is broken right out of the box… — FAIL: TestAgent (7.82s) agent_test.go:77: Error Trace: agent_test.go:77 agent_test.go:...
New
raul
Page 28: It implements io.ReaderAt on the store type. Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt? ...
New
swlaschin
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
leba0495
Hello! Thanks for the great book. I was attempting the Trie (chap 17) exercises and for number 4 the solution provided for the autocorre...
New
brunogirin
When trying to run tox in parallel as explained on page 151, I got the following error: tox: error: argument -p/–parallel: expected one...
New
dsmith42
Hey there, I’m enjoying this book and have learned a few things alredayd. However, in Chapter 4 I believe we are meant to see the “&gt;...
New
kolossal
Hi, I need some help, I’m new to rust and was learning through your book. but I got stuck at the last stage of distribution. Whenever I t...
New
mert
AWDWR 7, page 152, page 153: Hello everyone, I’m a little bit lost on the hotwire part. I didn’t fully understand it. On page 152 @rub...
New
New
roadbike
From page 13: On Python 3.7, you can install the libraries with pip by running these commands inside a Python venv using Visual Studio ...
New

Other popular topics Top

PragmaticBookshelf
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
AstonJ
Thanks to @foxtrottwist’s and @Tomas’s posts in this thread: Poll: Which code editor do you use? I bought Onivim! :nerd_face: https://on...
New
AstonJ
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
New
AstonJ
This looks like a stunning keycap set :orange_heart: A LEGENDARY KEYBOARD LIVES ON When you bought an Apple Macintosh computer in the e...
New
AstonJ
Do the test and post your score :nerd_face: :keyboard: If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
PragmaticBookshelf
Create efficient, elegant software tests in pytest, Python's most powerful testing framework. Brian Okken @brianokken Edited by Kat...
New
AstonJ
We’ve talked about his book briefly here but it is quickly becoming obsolete - so he’s decided to create a series of 7 podcasts, the firs...
New
PragmaticBookshelf
Author Spotlight Mike Riley @mriley This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
New
AstonJ
This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...
New
mindriot
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
New

Sub Categories: