devlog.md

Devlog

29th August 2024

Long Time No See

• Last on week was more execution and less learning
• Applying things learned and using it, helps you build better knowledge
• What did I execute? Created WebPage for OpenGeometry, created WASM package along with example to validate OpenMaths
• More on MVP coming soon

22nd August 2024

More on Match

• Match works with tuples as well, either all the elements can be tested for a match or even some elements in a partocular order can be tested as well.

match vector {
  (0, ..) => println!("First Element is 0"),
  (.., 0) => println!("Last Element is 0"),
  (0, 0, 0) => ("Zero Vector"),
  _ => println!("Default Case, don't bind to anything"),
}

• Match also works with array and can be tested for a value or can be indexed as well. The value needs to be mentioned explicitly and the index can be defined like variables and the values are binded to it

match vector {
  [0, y, z] => println!("First element is 0, y is {} and z is {}", y, z),
  [x, 0, ..] => println!("x is {}, Second element is 0", x),
  [x, rest @ ..] => println!("x is {}, rest of the elements are {:?}", x, rest),
}

• @ creates a slice of remaining elements and stores it inside rest

• enums can be tested using match as well

• more on binding later

Functions

• Declared using fn keyword, return type specified by ->
• There is a unique type of functions as well, called associated functions. They can be associated to a particular type. I like them!

struct Point3D {
  x: f64,
  y: f64,
  z: f64
}
  
impl Point3D {
  // called as a contructor
  fn set(x: f64, y: f64, z: f64) -> Point3D{
    Point3D { x: x, y: y, z: z}
  }

  // called as a method
  fn add (&self, other: &Point3D) -> Point3D {
    Point3D { x: self.x + other.x, y: self.y + other.y, z: self.z + other.z }
  }
}

21st August 2024

Loop

• Loop is created using loop keyword, break keyword will break the loop and continue skips the rest of the implementation and starts over
• Loops can be nested and should be anotated with ' with a name to it, e.g. 'outer: loop {}
• To break or continue the nested loop it can be done like this, break 'outer
• Loop can return value, if the value is attached after the break keyword. e.g. break result

While

• A while loop can be used until the condition is satisfied

while value < 10 {
  println!("number is {}", value)
  value += 1
}

For Loops

• for in can be used to iterate through Iterator, it is not anywhere close to TS
• The iterator initial value and final value should contain .. notation.

for n in 1..10 {
  println!("number is {}", n)
}

• In the above case loop will run until n is 9. To include 10 as well, loop should be like this for n in 1..=10

Match like Switch

• Works just like any other switch statement
• Match can be used as an expression as well and used later on. e.g. let switchStatement = match incomeTax { .... }

20th August 2024

TryFrom and TryInto

• Useful when doing type conversion that have some chances of failing and need special handling
• From and Into are for perfect conversions
• TryFrom and TryInto checks if the conversion can go bad, it is always better to use TryFrom and TryInto rather than relying on From (more safe)

String Operations

• String can be parsed using "5".parse().unwrap()
• type can be converted to string using e.g. rectangle.to_string()

Expressions

• Blocks are expressions too, the last statement is a return value of that block

let y = {
  let x = 1;
  let j = 2;
  x + j
}

println!("{}", y); // 3

Flow

• if-else is similar. The condition doesn't need to be surronded by ()
• All blocks return a value and the last expression does the same here

let num = 32;
let num_type = 
  if num/2 == 0 {
    println!("num is even");
    num * 10
  } else {
    println!("num is odd");
    num * 11
  };

println!("{}", num_type); // 3200

19th August 2024

Casting Continued..

• Casting works in some cases and not always, e.g. it is not possible to cast float to char
• Cast needs to be used wisely

Literals

• Numerical literals can be type annoted, the type needs to be added after the value
• e.g. let i = 3iu8

Inference & Aliasing

• Type inference can check for the array elements and infer the type based upon it's use
• Types can be renamed using aliasing method, for e.g. type KG = u32
• When using type aliasing, the types should UpperCamelCase names to prevent compiler warnings

Conversion

• From trait allows the way to create itself from another type
• Into is similar to From but it doesn't take value, rather called upon the variable
• From and Into are interchangeable

18th August 2024

More on Custom Types

• const and static can be used in Rust the same way done in another langauges like TS

Variable Bindings

• Rust provides type safety via statis typing, in most cases compiler infer type based on context
• By default, the variables are non-mutable in Rust, to create a mutable(ability to change) variable you need to use mut keyword.

let age = 20
age = 21 // ❌ error

let mut age = 20
age = 21 // ✅ works

• Shadow binding is allowed when a variable is declared in different scopes
• Redeclaration is allowed as well, this shadows the previous bindings

Casting

• Explicit Casting is possible using as keyword. let pi_int = pi_decimal as i32

17th August 2024

Strutctures

• Three types - Tuples, C type structs and Unit struct which are fieldless
• Structs can be destructured as well let Date { year, month, day, day_of_week } = date;
• Tuples and Struct appear to be same but the way they are accessed are different, structs cannot be indexed. There can be confusions when using tuple, I might avoid it as of now

Enums

• Allows the creation of type which can have one or more variant inside it
• It is recommended to keep enums in uppercase
• Didn't understood this well, need to come back later to this example

16th August 2024

Publishing to Rust Crates

• openmath seems to be already take, renaming the project to openmaths. I'm not obssesed with names, users don't care about name, they need something that works(IMO)
• Also, Crates- Package Registery for Rust, doesn't allow scoped crates, so the crate(package) name needs to be unique
• No sane person would publish a package in the first weeks of development, there are two things, I can't contain my excitement and second my aim is build and publish the library so I need to check the feasibility as well.
• Before you can push packages to crate, you have to login - cargo login
• Push the latest changes to git and then cargo package - creates a .crate file with source code
• License and Description are mandatory if you are building crates
• To publish the package - cargo publish

Basic Know-How

• Variables can be type annotated, also rust can infer types from context. Make sure to type annotate everything that is being used
• i32 is signed 32-bit integer and u32 is unsigned 32-bit integer
• Why type annotation is important? - println!("1 - 2 = {}", 1u32 - 2); when we run this, a compile error is thrown and it is easier to catch silly issues like this early on!
• _ using an underscore can improve readibility when dealing with large numbers, println!("One million is written as {}", 1_000_000u32); this will omit an underscore and 100000 will be printed to the console
• Camel Case notation is discouraged when creating variables, instead using an underscore is preferrred. Coming from JS this feels a little daunting but I hope it grows on me
• let numArr ⚠️
• let num_arr ✅

Tuples

• Tuples is a collection of data, it can be of similar data type or mixed
• It can be passed as a function parameter and can be used to return data as well
• It can be destructured like what we do with javascript objects
• Values can be extracted from tuple using index, e.g. let tup = ('i', 'n', 'd') when printed using println!("{}", tup.1) will print n
• Tuples can have multiple tuple within them - nested tuples
• Tuple can be printed, but it does not print more than 12 tuple memebers
• If a tuple contains a single value it should be separated by a comma, else rust considers it as a integer. (5u32,) - way to write single element tuple

Return of the function

• I found one thing strange, rust doesn't force you to mention return keyword unlike JS
• Don't let being perfectly idiomatic stop you from writing what you believe to be good code, I will use return

Array and Slices

• Similar to other languages, array is a collection of the same type T, stored in contiguous memory. Length is known at compile time
• let xs: [i32; 5] - here i32 is the type of elements present inside the xs array and 5 states the number of elements
• Length of an array can be fethced using array.len()
• Memory size can be computed using mem::size_of_val(&xs))
• Slices seem to be complex, need to look more deep into it!

Custom

• Custom types are created using struct and enum
• Constants can be created using const and static keyword

15th August 2024

Baby Steps

• Started follwing rust by example
• Cargo.toml file contains the dependencies, every dependecy is similar to a package/library in other programming languages
• To add dependency - cargo add packageName
• Using the package - use packageName
• disable unused code warning - #[allow(dead_code)], don't use it really - always keep your code clean

14th August 2024

Rust vs C++

• I have came to a conclusion that I need a robust math library for the Kernel Operations
• When I went to look for how these Math Libraries are structured, I found that the best solution these day is to use Native Code + WebAssembly.
• But I struggled to decide, with so many options, two langauges are mentioned the most C++ and Rust
• I'm no where a expert what is best, and then I thought why not create a package using both?
• This is not going to hurt me, surely I will have to invest double time, but I'm confident that this learning wouldn't go away!

Installing Rust and Project Setup

• On a mac, run this command curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
• Verify the installation by cargo --version, remember to close your terminal after the rust is installed
• Create new project - cargo new projectName