Understanding the Odin Programming Language

Hi Karl,

thank you for the update! Is it possible that you forgot to change the version number in the html file to 1.8?

Cheers

Hi Karl!! Will you print your book as a PDF too?? And will you do a new one about Odin and game programming??

Hi, reading the book now, it’s fantastic, I’ve found my C-replacement! Can’t wait to get to the parts on allocators and debuggers!

One thing I’ve noticed is that there’s not much about switch in there, beside how it’s used with enums and unions. For example I love how it can deal with ranges for numbers like case 0..<10:, or case 'a'..='z':, or that there is no default:, but instead it uses case:. I think these would be worthwhile additions.

Have a nice day!

I couldn't find info on using multithreading in Odin in the chapter list - does the book include info on how to handle threads?

Hello :wave,

I am considering buying the book, but before I do it, I have the following question:

I have noticed that periodically you update the content of the book (based on readers' feedback, new ideas which pop up in your mind, when it comes to what in your opinion would be useful for people to know etc.). Do I need to pay 20$ (+ VAT etc.) for every new  version that gets published? Should the answer to the previous question be "No, you do not have to pay additional money" - then how do I get access to the latest up to date version of the book (in the "Development log" section of this web page)?

I've never used itch.io before, which is why I am unfamiliar with how things work.

P.S. - considering all the positive feedback you are receiving - it feels like you'd benefit significantly from promoting your content more actively :) I only found the book by pure luck.

Kind regards,

Dunno if something can be done about this, but itch.io charged 25,5% for VAT, when the VAT for books in Finland is 14%.

Not asking for a refund or anything, but some other potential buyers may care more about this.

Waiting eagerly to read the book, your YouTube videos are a great source of inspiration!

Been working through the book slowly. Overall this has been really good so far.

Some feedback from someone who hasn’t done a ton with Pointers.

The chapter on pointers talks a lot about what pointers/addressables do, but doesn’t really discuss why we need pointers. Maybe it’s because Odin isn’t object oriented, likely because of the immutability aspect.

I have an idea, on this, but I feel like having examples on what not using pointers would do would be helpful. Most of the languages I’ve used so far, haven’t really been ones that used a lot of pointers.

Like, I’m pretty sure if I’m not using pointers, I’m essentially creating new data at new memory locations and losing the old memory or I’m running into errors.

I thought the addressables section may touch on this more, but not in as a direct way as I was hoping.

From the Addressable section, this confused me as well: “In which case element_pointer would not point to the tenth element of array. Instead, it would point to an in-between value.”

I think this is where emphasizing about getting a copy would be better. I had no idea what you meant by in-between value. I ended up doing some searching and confirmed my theory that element_pointer would contain a pointer to a copy of the data that would have been in the array.

I can see someone who isn’t as far along the path being very confused. I kinda feel like I understand, but will definitely have to do some simple experiments to confirm I’m understanding what I suspect.

Although Odin is rather a simple programming language, there are elements that one could find not so obvious and straightforward. This book helps to dispel misunderstandings and incorrect assumptions about Odin's inner behavior. And, honestly, it's neat to have such condensed source of information on hand, considering modest popularity of the language and lack of literature besides official overview and occasional articles.

That said, I have several nitpicks:

1) I think that not freeing memory in the end of a program is not generally a good advice, since, I believe, there are some OSes that do not free memory once a program is terminated.

2) In chapter 13.2

destroy_level :: proc(level: Level) {
    vmem.arena_destroy(&level.arena)
}

should be

destroy_level :: proc(level: ^Level) {
    vmem.arena_destroy(&level.arena)
}

since you'd get

Error: Cannot take the pointer address of 'level.arena'

otherwise.

3) In chapter 18.4

If you want a file to not compile on macOS and not compile on Linux, then add this to the top of the file:

#+build !windows
#+build !linux

should probably be

#+build !darwin
#+build !linux

4) In chapter 12.4

if logh_err == os.ERROR_NONE {
    log.destroy_file_logger(logger)
    os.close(logh)
}

there is no need to close handle, because

log.destroy_file_logger(logger)

looks like

destroy_file_logger :: proc(log: Logger, allocator := context.allocator) {
    data := cast(^File_Console_Logger_Data)log.data
    if data.file_handle != os.INVALID_HANDLE {
        os.close(data.file_handle)
    }
    free(data, allocator)
}

and calling

os.close(logh)

may lead to the

An invalid handle was specified.

error.

Hey Karl, the book is fantastic, I have learned so much about this language even in the space of a few days. One observation I wanted to ask, in section 10.2.5 you illustrate an application for maps by building a set, and say that Odin doesn't have any special support for sets, but I thought bit sets were exactly that?

https://odin-lang.org/docs/overview/#bit-sets

It even supports "overloading" of operators so you can do unions and such. Is there a fundamental difference here? Thanks again for such a great book!

EDIT: D'oh, my bad, your set example using a map allows sets of arbitrary type whereas bitsets are more limited. Never mind!

Read three pages and zero cats. Disappointed.
Well-written, easy to read and even to understand (sometimes). I like it a lot. 

As far as I’ve read, the book is great , well structured and well written. It’s a must have for all the Odin programmers, ans perhaps for all the programmers who want to discover the great coding language that Odin Is.

I've just barely started it and I'm already loving it! Everything is organized clearly and beautifully, explanations are easy to follow with nice illustrations that help a lot!

Such a well-written and beautifully-designed book on Odin! Thank you for your hard work!