I continued reading Command Line Applications in Rust
Learnt that testing is easy. Any function that has #[test] above it, will be found (across any files) and used by cargo test
Couple of interesting crates :
exitcode It has quite well defined exit codes. They come from FreeBSD I wish other languages / frameworks had something similar proptest is a property testing framework Based on python’s Hypothesis I need to spend time actually trying this human-panic Generates report file on panic Shows nice (if a bit long) message to the user, asking them to (optionally) email the report file to the developer 🤯 Things to explore:
Today I started reading Command Line Applications in Rust
Even though I have not finished reading “the book”, I am (by now) familiar with enough rust code that reading this book was kinda refreshing.
Few important things I picked up :
{:?} in println! is called debug representation (quite useful for .. debugging 😄) Custom data types can add support for {:?} for debugging and logging, one needs to add a #[derive(Debug) above their definition.
Technically this may be more like day 8 or 9, cause I did read some stuff from the rust book in last few days, and made note here
Nothing improves your understanding better than doing
– Me 😄
I was trying accessing the individual fields in tuple struct using dot notation via the index
Since the rust book does not have an example of it, I used rust playground (Awesome resource BTW) and just printed stuff.
When I started reading about Ownership, I was thinking
I have done C. I understand memory
But Rust book explains :
If you are familiar with systems programming, you might think of memory at a low level like “memory is an array of bytes” or “memory is the pointers I get back from malloc”. .. The low-level model is too concrete to explain how Rust works. Rust does not allow you to interpret memory as an array of bytes, for instance.
I want to access Bard API via Rust, but it will take some time.
Here are the things I did today.
First, I tried (successfully) to access an URL via Rust code. ✅
I used the reqwest module.
I just added this dependency in my Cargo.toml and (like in other languages) the dependency hell was let loose 😄
67 other modules were added to the Cargo.lock!
I also learnt to use global variables in Rust.
Started with (optional) assignment at the end of “Programming Concept” chapter : Convert temperature between Celsius and Fahreinheit. 1
Since the algorithm itself is not part of the learning the language, I asked Google Bard about the formula.
It was nice working on some code after a while (Aside from work, I mean)
Once again, I realized that compiler is very helpful 😍
I started simple.
Breaking down functionality into smaller functions.
Today I finished Functions and Control Flow etc.
While these are not new “concepts” for me, one always learns something new when learning a new language.
Two things I learnt:
I liked the fact that rust does not evaluate anything other than boolean as truthy like both python and ruby loop can have labels, and can be used with break and continue to indicate where should the execution continue
Today I started with Data Types
While most of it is intuitive, it is useful to go over the documentation.
e.g. For tuple, I had expected that to access specific index, syntax would be mytuple[0]. mytuple.0 was not I had expected.
I also tried to print the tuple.
In the process, I learnt about pretty printing only from the compiler errors.
The compiler errors are so descriptive 😍
Here is the code in case you are interested
Today I finished the Number guessing game
During the early part of the code, my mind started thinking “How will comparing string input from the user, work with a number? 🤔” (💪 of having gone through such issues numerous times over the years)
Of course, it was explained later.
I was a bit disappointed that the code paniced upon entering non-number 😞 especially after the expect clause.
Turns out that is expected behaviour.