PragProg Customers

Hands-on Rust: why a second clone?

mikecargal

mikecargal

Hands-on Rust: why a second clone?

Title: Hands-On Rust (Chapter 10: Iterating Away the Chaos)

in the iteration function, why is it necessary to return a clone of new_tiles (which was already cloned from map.tiles?)

3 comments
#question/book-hands-on-rust
5 571 3

Marked As Solved

herbert

herbert

Author of Hands-on Rust

I have a build (I wish I had room to include it in the book) that plays itself over and over. After a few hours, no errors with the clone omitted - so it’ll be trimmed for the next beta. Thanks! :slight_smile:

1
Post #4

Also Liked

mikecargal

mikecargal

Yeah, I skipped it, and now that I have things wired up it seems to work fine. Guess I’ll let you know if I stumble across some issue.

2
Post #3
herbert

herbert

Author of Hands-on Rust

That’s actually a very good question. It appears to work fine without it (it replaces the copy with a move; both compile down to memcpy so it winds up not making a lot of difference in terms of performance). My notes indicate that I had problems with an earlier Rust compiler there, so I’m going to test the heck out of it before committing the change. Thanks!

1
Post #2

Where Next?

View thread on forum
View Hands On Rust's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
question
Home PragProg Customers
#question/book-hands-on-rust
5 571 3
Last post

Popular Pragmatic Bookshelf topics Top

iPaul
PragProg Customers

The Definitive ANTLR 4 Reference: Program deprecation warning
page 37 ANTLRInputStream input = new ANTLRInputStream(is); as of ANTLR 4 .8 should be: CharStream stream = CharStreams.fromStream(i...
#errata/book-the-definitive-antlr-4-reference
4 987 0
New
edruder
PragProg Customers

Docker for Rails Developers: Notes for Rails 6.1, Ruby 2.7.2
I thought that there might be interest in using the book with Rails 6.1 and Ruby 2.7.2. I’ll note what I needed to do differently here. ...
/book-docker-for-rails-developers
9 1177 1
New
raul
PragProg Customers

Distributed Services with Go: Chapter 1 Suggestions
Hi Travis! Thank you for the cool book! :slight_smile: I made a list of issues and thought I could post them chapter by chapter. I’m rev...
#errata/book-distributed-services-with-go
2 1185 3
New
AleksandrKudashkin
PragProg Customers

Modern Front-End Development for Rails: B7 no main folder in the source code (page xv)
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...
#errata/book-modern-front-end-development-for-rails
2 1452 11
New
hgkjshegfskef
PragProg Customers

The Ray Tracer Challenge: cannot pass scaling test (page 69-70)
The test is as follows: Scenario: Intersecting a scaled sphere with a ray Given r ← ray(point(0, 0, -5), vector(0, 0, 1)) And s ← sphere...
#question/book-the-ray-tracer-challenge
1 1093 4
New
adamwoolhether
PragProg Customers

Powerful Command-Line Applications in Go: Exercise Solutions (many pages)
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
#question/book-powerful-command-line-applications-in-go
17 1396 9
New
akraut
PragProg Customers

Programming Phoenix LiveView: Display Image Uploads (pdf p142)
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error. lib/pento_web/live/product_l...
#errata/book-programming-phoenix-liveview
2 2102 9
New
EdBorn
PragProg Customers

Agile Web Development with Rails 7: (page 70)
Title: Agile Web Development with Rails 7: (page 70) I am running windows 11 pro with rails 7.0.3 and ruby 3.1.2p20 (2022-04-12 revision...
#question/book-agile-web-development-with-rails-7
0 1129 1
New
dtonhofer
PragProg Customers

The Definitive ANTLR 4 Reference - "Java.g4" grammer (used on page 40) no longer passes ANTLR
@parrt In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
#errata/book-the-definitive-antlr-4-reference
0 1020 3
New
redconfetti
PragProg Customers

Docker for Rails Developers - 'docker-machine' command deprecated (page 156)
Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
/book-docker-for-rails-developers#suggestion
0 896 0
New

Other popular topics Top

Devtalk
General Dev>Dev Chat

HELLO WORLD (Introductions thread!)
Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:
#community
481 6762 116
New
DevotionGeo
Backend>Chat

What is the reason behind Rust’s web framework, Rocket, not performing as well as expected in the Techempower benchmarks?
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
#web-frameworks/rust
36 7463 11
New
Exadra37
General Dev>Hardware

What monitor(s) do you have for programming?
Please tell us what is your preferred monitor setup for programming(not gaming) and why you have chosen it. Does your monitor have eye p...
#monitors#coding#programming#development
227 11362 88
New
AstonJ
General Dev>Hardware

GMK Serika Keycaps - Serika 2 available to order now!
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...
/keyboards#keycaps#mechanical-keyboards
9 5097 7
New
AstonJ
Backend>Chat

Rails console using 100% CPU in dev (fix)
If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...
/ruby/rails
3 4188 3
New
PragmaticBookshelf
Backend>Learning Resources

Concurrent Data Processing in Elixir
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
pragprog.com
#pragprog/elixir#published-book/book-concurrent-data-processing-in-elixir
78 6059 24
New
AstonJ
General Dev>Dev Chat

Languages Without Garbage Collection
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
#garbage-collection
21 5575 7
New
First poster: CommunityNews
AI>In The News

How to fix the eyes in AI-generated images
aidemos.info
0 4508 0
New
husaindevelop
Android>Questions

Clipboard readtext not working in android webview
Inside our android webview app, we are trying to paste the copied content from another app eg (notes) using navigator.clipboard.readtext ...
#android#clipboard
1 5651 0
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Peter Ullrich (Author) Interview and AMA!
Author Spotlight: Peter Ullrich @PJUllrich Data is at the core of every business, but it is useless if nobody can access and analyze ...
/elixir/phoenix/book-building-table-views-with-phoenix-liveview
72 4765 21
New
Back to top

Latest in Hands-on Rust

Hands-on Rust Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap