If you are from Java background, then you would be familiar with Exception Handling where you are forced to use it extensively. But, most of the modern programming language, like Rust doesn't support Exception Handling. You might wonder how is this possible! In these slides, you will walk through how rust handles exception problem without having exceptions. These slides also cover: 1. Brief introduction about Rust Programming Language. 2. How Rust handles errors in Compile Time. 3. Dealing with Exception handling in Other Languages vs Rust.

1. Live Without
Exceptions In
Rust
Presented By: Ayush Kumar Mishra
Sr. Lead Consultant
Knoldus Inc.
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2. About Knoldus
Knoldus is a technology consulting firm with focus on modernizing the digital systems
at the pace your business demands.
DevOps
Functional. Reactive. Cloud Native

3. 01 Introduction to Rust
02 Dealing with Exception handling in Other Languages
03 Live without Exception in Rust
04 Error Handling in Rust
Our Agenda

4. 1
2
3
4
Best known for being a system language
Doesn't have Garbage Collection
It has its own package manager Cargo
Focused on safety, speed, and concurrency
“A systems programming
language that runs blazingly
fast, prevents segfaults, and
guarantees thread safety. ”
Introduction to Rust

5. Strict exception
handling
Java01
Exceptions-agnostic
C
03
Weak exception
handling
C++, Python, Ruby
02
By monadic types
Rust, Scala, Swift04
Dealing with Exception handling in
Other Languages

6. Live without Exception in Rust

7. Live without Exception in Rust
1 Rust doesn’t support throwing exceptions, nor does it support catching them

8. Live without Exception in Rust
2 Exceptions bubble up by default, which may be surprising / unexpected

9. Live without Exception in Rust
3 Rust does not use the concept of null nil undefined types
enum Result<T, E> {
Ok(T),
Err(E),
}
enum Option<T> {
None,
Some(T),
}

10. Live without Exception in Rust
4 In Rust, there is no way for code to interact with objects in an invalid state

11. BANNER INFOGRAPHICInsert Your Subtitle Here
Unrecoverable01
Recoverable 02
fn main() {
panic!("Quit from here!");
}
fn parse_string_to_int(str: &str) {
match str.parse::<i32>() {
Ok(t) => println!("Here is parsed integer {}!", t),
Err(e) => println!("There was a problem {:?}", e),
};
}
Error Handling in Rust

12. BANNER INFOGRAPHICInsert Your Subtitle Here
When to use panic!
When the panic! macro executes
1) When there is some unexpected error
2) When we are not using any debugger or proper logs
1) Unwinding
2) Aborting (panic = 'abort')
panic!

13. Option<T> or Result<T, E>
fn match_color(color: Option<&str>) {
match color {
Some("Red") => println!("Hey I got Red T-shirt"),
Some(c) => println!("I don't like {} T-shirt", c),
None => println!("No T-shirt"),
}
}
fn parse_string_to_int(str: &str) {
match str.parse::<i32>() {
Ok(t) => println!("Here is parsed integer {}!", t),
Err(e) => println!("There is a problem {:?}", e),
};
}

14. 01
References
https://doc.rust-lang.org/book/ch09-00-error-handling.html
https://medium.com/learning-rust/rust-error-handling-72a8e036dd3
https://stevedonovan.github.io/rust-gentle-intro/6-error-handling.html
https://dev.to/saiumesh/error-handling-in-rust-programming-language-3g4
https://blog.knoldus.com/you-can-live-without-exceptions-if-you-are-using-rust/

15. Subscribe

16. Thank You!
@ayushmishra2005
ayush@knoldus.com