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First Week learning rust

Enyel Sequeira on November 22, 2021

My First week learning Rust using (The Rust Programming Language) "The Book" Why Rust? As a Front-End developer, there is a ...

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peerreynders • Nov 23 '21

By default when declaring a variable that becomes immutable, however, it is possible to make it mutable by adding the mut keyword like so let mut number.

In some ways this perspective — fuelled by the chosen syntax — is bound to create confusion later.

When it comes to Rust train your brain ASAP to make the following automatic substitutions:

immutable -> shared access
mutable -> exclusive access (unique)

i.e. "shared" values cannot be mutated and "exclusive" values cannot be "shared".

The immutable ⟷ mutable tension is only a consequence of the primary shared ⟷ exclusive tension.

By default values are assumed to have shared access and therefore have to be explicitly marked for exclusive access (mut).

See

Enyel Sequeira • Nov 23 '21

Nice thank you the tips, specially that link about ownership is a lot at first

Ben Lovy • Nov 22 '21

You're just in time, implicit named capture is already available in nightly/unstable! format!(" Hello {name}!"); is indeed coming to stable Rust really soon.

Alexander B.K. • Nov 23 '21

I have build a very simple, console hello world program using Rust, Go and C++ on Windows. The executable file size is surprising to me :
Rust is 4Mb, Go is about 3Mb, while C++ is only 171kb (as expected). For C++ I use g++ compiler. I installed Rust using its GNU version of Msi installer.
Can you explain why ?
When I have developed a relatively large web app using PHP+Laravel in backend as well as React, Bootstrap and other 3rd party libs in frontend that has a lot of forms, the bundle size was about 8Mb which I thought was very big. I couldn't use code-splitting at that time.
Now, seeing the 3-4Mb for a console hello world that basically only has one printLn using both Rust and Go seems to be unacceptable.

Ben Lovy • Nov 23 '21

I don't know about Go, so I can't speak for that. With Rust, you're seeing these sizes due to static linking, and symbols being included in the binary. On Linux, a hello-world compiled with --release generates a 3.7M executable. Just running strip on this executable reduces the size to 310k. You can also se size-related optimizations in your profile:

[profile.release]
opt-level = "z"
lto = true

Other tweakables include panic behavior - you can remove the unwinding mechanism using this:

[profile.release]
panic = "abort"

So, yes, while the defaults produce some hefty executables, Rust does expose tools to more finely tweak your result. This repo provides a much more comprehensive overview.

Alexander B.K. • Nov 24 '21

Thanks for the answer. This is just a start for my journey of Rust. I have a plan to try it for web backend after reading your post about it. We know that the book also has a chapter on web server that I can use for starting point.

peerreynders • Nov 23 '21 • Edited

The executable file size is surprising to me : Rust is 4Mb …

Quote

The executable is 3.5 MiB but there's only 212 KiB of actual executable code, the rest is debug symbols.

Minimizing Rust Binary Size

With C/C++ knowledge Programming Rust 2e may be a better starting point — though if that knowledge is spotty, it could still become a hard slog.

TinyGo - Go compiler for small places

FYI: Zig

Alexander B.K. • Nov 24 '21

Thanks for the explanation, sir.

Alexander B.K. • Nov 23 '21

It is interesting how Rust implements OOP, specifically how it defines a method. Now it reminds me of Go, being a non-OOP language, how it defines a method using a receiver argument which can be a pointer.
Rust is not a fully OOP or even not OOP when using certain definition, unlike C++, Java or C# which are fully OOP. But I like when it provides Struct that we have known in C/C++ and also find in Go. And it provides pointer and smart pointer too. This is why I think, if I have time, I can learn Rust, Go and C++ (relearn) in the same week. :)

Enyel Sequeira • Nov 23 '21

Yes, I was reading about it, it will be cool, makes it more inuitive 😃

Alexander B.K. • Nov 23 '21

When I read the book the 1s time, one thing I wanted to know whether Rust provided similar kind of pointers that C/C++ had, or how it managed memory. Then I found one new concept : Ownership which was interesting. But I stopped reading the documentation/book because of other priorities, knowing that it would take long time to learn.
Whenever I think to learn Rust, though, I also remember C++ which I want to re-learn in the correct way using Stanley Lippman's book (C++ Primer).
Ideally, I want to manage my time to learn Rust and C++. I have installed GCC compiler for writing C++ code. I expect I can install Rust which can use GNU compiler instead of MSVC.

Enyel Sequeira • Nov 23 '21

I am actuall at the part with owneship, and I found it a bit confusing, since this is my first time learning a low level language, I never really had to think about these factors. But it is definetely interesting to learn about it, I have seen that just with everything theres a trade-off though

sionkim00 • Nov 26 '21

Hi Enyel, can you share Practicum discount code with me? I'm interested in their web dev course. Thank you!

Enyel Sequeira • Nov 28 '21

Hello, yes. Just saw your message if you have twitter please message me there enyelsequeira