cargo example1 page 11

[lsatenstein]

Problem

First example that is supposed to compile cleanly

$ git clone https://github.com/rust-lang/regex.git
$ cd regex

$ cargo build
Compiling regex v1.5.0 (file:///path/to/package/regex)

leslie@Fed35 ~$ cd regex/
leslie@Fed35 regex$ cargo build
GOT
Updating crates.io index
Compiling memchr v2.4.1
Compiling regex-syntax v0.6.25 (/home/leslie/regex/regex-syntax)
Compiling aho-corasick v0.7.18
warning: field is never read: printer
--> regex-syntax/src/ast/print.rs:66:5
|
66 | printer: &'p mut Printer,
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[warn(dead_code)] on by default

warning: field is never read: printer
--> regex-syntax/src/hir/print.rs:74:5
|
74 | printer: &'p mut Printer,
| ^^^^^^^^^^^^^^^^^^^^^^^^

Compiling regex v1.5.4 (/home/leslie/regex)
warning: regex-syntax (lib) generated 2 warnings
Finished dev [unoptimized + debuginfo] target(s) in 5.10s

Steps

refer to listing

Possible Solution(s)

Please correct syntax errors so cloned example compiles cleanly

Notes

No response

Version

cargo --version
cargo 1.57.0 (b2e52d7ca 2021-10-21)

[Eh2406]

What research have you done? Why do you think this is a problem with cargo as opposed to a problem with regex?

[lsatenstein]

I am a beginner. I was following the guide.Step 1 .. Step2 ... step3 Step two was to dl and run the rustc.Step 3 was to use cargo.When the problem occurred, I just did the report. BTW, I am really just starting with Rust, after 20 years of C. I will never work in rust, except for some self-created project. Regards  Leslie Leslie Satenstein Montréal Québec, Canada On Saturday, January 8, 2022, 01:27:30 p.m. EST, Jacob Finkelman ***@***.***> wrote: What research have you done? Why do you think this is a problem with cargo as opposed to a problem with regex? — Reply to this email directly, view it on GitHub, or unsubscribe. Triage notifications on the go with GitHub Mobile for iOS or Android. You are receiving this because you authored the thread.Message ID: ***@***.***>

[Eh2406]

Welcome to the community! I'm sorry you're having trouble.

Which guide were you following?

[lsatenstein]

The book from the website. Regards  Leslie Leslie Satenstein Montréal Québec, Canada On Monday, January 10, 2022, 07:05:57 p.m. EST, Jacob Finkelman ***@***.***> wrote: Welcome to the community! I'm sorry you're having trouble. Which guide were you following? — Reply to this email directly, view it on GitHub, or unsubscribe. Triage notifications on the go with GitHub Mobile for iOS or Android. You are receiving this because you authored the thread.Message ID: ***@***.***>

[Eh2406]

by "the book" do you mean "The Rust Programming Language"? If so I don't have a print copy of the current edition so do not know what is on page 11.

Step 1 .. Step2 ... step3

I am guessing you are referring to https://doc.rust-lang.org/book/ch01-03-hello-cargo.html but that no where mentions regex.

If you are having a problem with the book it is maintained at https://github.com/rust-lang/book
If you are having a problem with the regex it is maintained at https://github.com/rust-lang/regex

Cargo is a package manager, we can not be responsible for keeping all rust code working even when the code is build with Cargo.

[ehuss]

@Eh2406 I think they are referring to https://doc.rust-lang.org/cargo/guide/working-on-an-existing-project.html

@lsatenstein Thanks for opening this issue! I think it is not unusual for projects to start to have warnings with newer versions of the compiler. I believe this particular issue was introduced by rust-lang/rust#85200. Indeed those fields appear to be unused. I don't have time to try to develop a PR to fix it, but if you want to write an issue at https://github.com/rust-lang/regex, that would be helpful. Or, if you are feeling adventurous, you can work on a PR to fix the warnings.

I'm going to close, as I think the example in the documentation is fine. Real-world projects will have warnings like this, and I don't think it is anything to be particularly concerned about.

I'm going to close as this is more of an issue with the regex project.

[lsatenstein]

Thank you all for the prompt response. I am doing my frst pass through Rustland. On the second pass, I will do the deep learning and on the third pass, I will write some code that I will share.

Again thank you!!
Leslie

[lsatenstein]

If you are wondering why 3 passes to learn, it comes from my teaching / learning experience.
First step I am going to tell you what I am going to tell you, And I peruse the manuals and youtube videos.
2nd step I am telling you what I said I would tell you in more detail. Do you remember the contents from step 1?
3rd step This is what I told you, now go out into Rustland and make use of your learned knowledge.