r3bl_rs_utils

Usage
redux
Macros
- Declarative
  - debug!
- Procedural
  - #[derive(Builder)]
  - make_struct_safe_to_share_and_mutate!
tree_memory_arena (non-binary tree data structure)
utils
tui (experimental)
Stability

This library provides utility functions:

Thread safe asynchronous Redux library (uses Tokio to run subscribers and middleware in separate tasks). The reducer functions are run in sequence (not in Tokio tasks).
Declarative macros, and procedural macros (both function like and derive) to avoid having to write lots of boilerplate code for many common (and complex) tasks.
Non binary tree data structure inspired by memory arenas, that is thread safe and supports parallel tree walking.
Functions to unwrap deeply nested objects inspired by Kotlin scope functions.
Capabilities to make it easier to build TUIs (Text User Interface apps) in Rust. This is currently experimental and is being actively developed.

💡 To learn more about this library, please read how it was built on developerlife.com:

https://developerlife.com/2022/02/24/rust-non-binary-tree/

https://developerlife.com/2022/03/12/rust-redux/

https://developerlife.com/2022/03/30/rust-proc-macro/

💡 You can also read all the Rust content on developerlife.com here. Also, the equivalent of this library is available for TypeScript and is called r3bl-ts-utils.

Usage

Please add the following to your Cargo.toml file:

[dependencies]
r3bl_rs_utils = "0.7.1"

redux

Store is thread safe and asynchronous (using Tokio). The middleware and subscribers will be run in asynchronously via Tokio tasks. But the reducer functions will be run in sequence (not in separate Tokio tasks).

⚡ Any functions or blocks that you write which uses the Redux library will have to be marked async as well. And you will have to spawn the Tokio runtime by using the #[tokio::main] macro. If you use the default runtime then Tokio will use multiple threads and its task stealing implementation to give you parallel and concurrent behavior. You can also use the single threaded runtime; its really up to you.

Here's an example of how to use it. Let's say we have the following action enum, and state struct.

/// Action enum.
#[derive(Debug, PartialEq, Eq, Hash, Clone)]
pub enum Action {
  Add(i32, i32),
  AddPop(i32),
  Clear,
  MiddlewareCreateClearAction,
}

/// State.
#[derive(Clone, Default, PartialEq, Debug, Hash)]
pub struct State {
  pub stack: Vec<i32>,
}

Here's an example of the reducer function.

// Reducer function (pure).
let reducer_fn = |state: &State, action: &Action| match action {
  Action::Add(a, b) => {
    let sum = a + b;
    State { stack: vec![sum] }
  }
  Action::AddPop(a) => {
    let sum = a + state.stack[0];
    State { stack: vec![sum] }
  }
  Action::Clear => State { stack: vec![] },
  _ => state.clone(),
};

Here's an example of an async subscriber function (which are run in parallel after an action is dispatched). The following example uses a lambda that captures a shared object. This is a pretty common pattern that you might encounter when creating subscribers that share state in your enclosing block or scope.

// This shared object is used to collect results from the subscriber function & test it later.
let shared_object = Arc::new(Mutex::new(Vec::<i32>::new()));
// This subscriber function is curried to capture a reference to the shared object.
let subscriber_fn = with(shared_object.clone(), |it| {
  let curried_fn = move |state: State| {
    let mut stack = it.lock().unwrap();
    stack.push(state.stack[0]);
  };
  curried_fn
});

Here are two types of async middleware functions. One that returns an action (which will get dispatched once this middleware returns), and another that doesn't return anything (like a logger middleware that just dumps the current action to the console). Note that both these functions share the shared_object reference from above.

// This middleware function is curried to capture a reference to the shared object.
let mw_returns_none = with(shared_object.clone(), |it| {
  let curried_fn = move |action: Action| {
    let mut stack = it.lock().unwrap();
    match action {
      Action::Add(_, _) => stack.push(-1),
      Action::AddPop(_) => stack.push(-2),
      Action::Clear => stack.push(-3),
      _ => {}
    }
    None
  };
  curried_fn
});

// This middleware function is curried to capture a reference to the shared object.
let mw_returns_action = with(shared_object.clone(), |it| {
  let curried_fn = move |action: Action| {
    let mut stack = it.lock().unwrap();
    match action {
      Action::MiddlewareCreateClearAction => stack.push(-4),
      _ => {}
    }
    Some(Action::Clear)
  };
  curried_fn
});

Here's how you can setup a store with the above reducer, middleware, and subscriber functions.

// Setup store.
let mut store = Store::<State, Action>::new();
store
  .add_reducer(ReducerFnWrapper::new(reducer_fn))
  .await
  .add_subscriber(SafeSubscriberFnWrapper::new(subscriber_fn))
  .await
  .add_middleware(SafeMiddlewareFnWrapper::new(mw_returns_none))
  .await;

Finally here's an example of how to dispatch an action in a test. You can dispatch actions asynchronously using dispatch_spawn() which is "fire and forget" meaning that the caller won't block or wait for the dispatch_spawn() to return. Then you can dispatch actions synchronously if that's what you would like using dispatch().

// Test reducer and subscriber by dispatching Add and AddPop actions asynchronously.
store.dispatch_spawn(Action::Add(10, 10)).await;
store.dispatch(&Action::Add(1, 2)).await;
assert_eq!(shared_object.lock().unwrap().pop(), Some(3));
store.dispatch(&Action::AddPop(1)).await;
assert_eq!(shared_object.lock().unwrap().pop(), Some(21));
store.clear_subscribers().await;

// Test async middleware: mw_returns_action.
shared_object.lock().unwrap().clear();
store
  .add_middleware(SafeMiddlewareFnWrapper::new(mw_returns_action))
  .dispatch(&Action::MiddlewareCreateClearAction)
  .await;
assert_eq!(store.get_state().stack.len(), 0);
assert_eq!(shared_object.lock().unwrap().pop(), Some(-4));

Macros

Declarative

There are quite a few declarative macros that you will find in the library. They tend to be used internally in the implementation of the library itself. Here are some that are actually externally exposed via #[macro_export].

debug!

This is a really simple macro to make it effortless to use the color console logger. It takes an identifier as an argument. It simply dumps an arrow symbol, followed by the identifier (stringified) along with the value that it contains (using the Debug formatter). All of the output is colorized for easy readability. You can use it like this.

let my_string = "Hello World!";
debug!(my_string);

Procedural

All the procedural macros are organized in 3 crates using an internal or core crate: the public crate, an internal or core crate, and the proc macro crate.

#[derive(Builder)]

This derive macro makes it easy to generate builders when annotating a struct or enum. It generates It has full support for generics. It can be used like this.

#[derive(Builder)]
struct Point<X, Y>
where
  X: std::fmt::Display + Clone,
  Y: std::fmt::Display + Clone,
{
  x: X,
  y: Y,
}

let my_pt: Point<i32, i32> = PointBuilder::new()
  .set_x(1 as i32)
  .set_y(2 as i32)
  .build();

assert_eq!(my_pt.x, 1);
assert_eq!(my_pt.y, 2);

make_struct_safe_to_share_and_mutate!

This function like macro (with custom syntax) makes it easy to manage this pattern (which we call the "manager" of "things").

🪄 You can read all about it here.

The idea is to make it easy to manage shareability and interior mutability of a struct.

This struct gets wrapped in a RwLock for thread safety.
That is then wrapped inside an Arc so we can share it across threads.
Additionally it works w/ Tokio so that it is totally async. It also fully supports generics and trait bounds w/ an optional where clause.

Here's a very simple usage:

make_struct_safe_to_share_and_mutate! {
  named MyMapManager<K, V>
  where K: Default + Send + Sync + 'static, V: Default + Send + Sync + 'static
  containing my_map
  of_type std::collections::HashMap<K, V>
}

Here's an async example.

#[tokio::test]
async fn test_custom_syntax_no_where_clause() {
  make_struct_safe_to_share_and_mutate! {
    named StringMap<K, V>
    // where is optional and is missing here.
    containing my_map
    of_type std::collections::HashMap<K, V>
  }

  let my_manager: StringMap<String, String> = StringMap::default();
  let locked_map = my_manager.my_map.read().await;
  assert_eq!(locked_map.len(), 0);
  drop(locked_map);
}

tree_memory_arena (non-binary tree data structure)

[Arena] and [MTArena] types are the implementation of a non-binary tree data structure that is inspired by memory arenas.

Here's a simple example of how to use the [Arena] type:

use r3bl_rs_utils::{
  tree_memory_arena::{Arena, HasId, MTArena, ResultUidList},
  utils::{style_primary, style_prompt},
};

let mut arena = Arena::<usize>::new();
let node_1_value = 42 as usize;
let node_1_id = arena.add_new_node(node_1_value, None);
println!("{} {:#?}", style_primary("node_1_id"), node_1_id);
assert_eq!(node_1_id, 0);

Here's how you get weak and strong references from the arena (tree), and tree walk:

use r3bl_rs_utils::{
  tree_memory_arena::{Arena, HasId, MTArena, ResultUidList},
  utils::{style_primary, style_prompt},
};

let mut arena = Arena::<usize>::new();
let node_1_value = 42 as usize;
let node_1_id = arena.add_new_node(node_1_value, None);

{
  assert!(arena.get_node_arc(&node_1_id).is_some());
  let node_1_ref = dbg!(arena.get_node_arc(&node_1_id).unwrap());
  let node_1_ref_weak = arena.get_node_arc_weak(&node_1_id).unwrap();
  assert_eq!(node_1_ref.read().unwrap().payload, node_1_value);
  assert_eq!(
    node_1_ref_weak.upgrade().unwrap().read().unwrap().payload,
    42
  );
}

{
  let node_id_dne = 200 as usize;
  assert!(arena.get_node_arc(&node_id_dne).is_none());
}

{
  let node_1_id = 0 as usize;
  let node_list = dbg!(arena.tree_walk_dfs(&node_1_id).unwrap());
  assert_eq!(node_list.len(), 1);
  assert_eq!(node_list, vec![0]);
}

Here's an example of how to use the [MTArena] type:

use std::{
  sync::Arc,
  thread::{self, JoinHandle},
};

use r3bl_rs_utils::{
  tree_memory_arena::{Arena, HasId, MTArena, ResultUidList},
  utils::{style_primary, style_prompt},
};

type ThreadResult = Vec<usize>;
type Handles = Vec<JoinHandle<ThreadResult>>;

let mut handles: Handles = Vec::new();
let arena = MTArena::<String>::new();

// Thread 1 - add root. Spawn and wait (since the 2 threads below need the root).
{
  let arena_arc = arena.get_arena_arc();
  let thread = thread::spawn(move || {
    let mut arena_write = arena_arc.write().unwrap();
    let root = arena_write.add_new_node("foo".to_string(), None);
    vec![root]
  });
  thread.join().unwrap();
}

// Perform tree walking in parallel. Note the lambda does capture many enclosing variable context.
{
  let arena_arc = arena.get_arena_arc();
  let fn_arc = Arc::new(move |uid, payload| {
    println!(
      "{} {} {} Arena weak_count:{} strong_count:{}",
      style_primary("walker_fn - closure"),
      uid,
      payload,
      Arc::weak_count(&arena_arc),
      Arc::weak_count(&arena_arc)
    );
  });

  // Walk tree w/ a new thread using arc to lambda.
  {
    let thread_handle: JoinHandle<ResultUidList> =
      arena.tree_walk_parallel(&0, fn_arc.clone());

    let result_node_list = thread_handle.join().unwrap();
    println!("{:#?}", result_node_list);
  }

  // Walk tree w/ a new thread using arc to lambda.
  {
    let thread_handle: JoinHandle<ResultUidList> =
      arena.tree_walk_parallel(&1, fn_arc.clone());

    let result_node_list = thread_handle.join().unwrap();
    println!("{:#?}", result_node_list);
  }
}

📜 There are more complex ways of using [Arena] and [MTArena]. Please look at these extensive integration tests that put them thru their paces here.

utils

LazyMemoValues

This struct allows users to create a lazy hash map. A function must be provided that computes the values when they are first requested. These values are cached for the lifetime this struct. Here's an example.

use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
use r3bl_rs_utils::utils::LazyMemoValues;

// These are copied in the closure below.
let arc_atomic_count = AtomicUsize::new(0);
let mut a_variable = 123;
let mut a_flag = false;

let mut generate_value_fn = LazyMemoValues::new(|it| {
  arc_atomic_count.fetch_add(1, SeqCst);
  a_variable = 12;
  a_flag = true;
  a_variable + it
});

assert_eq!(arc_atomic_count.load(SeqCst), 0);
assert_eq!(generate_value_fn.get_ref(&1), &13);
assert_eq!(arc_atomic_count.load(SeqCst), 1);
assert_eq!(generate_value_fn.get_ref(&1), &13); // Won't regenerate the value.
assert_eq!(arc_atomic_count.load(SeqCst), 1); // Doesn't change.

tty

This module contains a set of functions to make it easier to work with terminals.

The following is an example of how to use is_stdin_piped():

fn run(args: Vec<String>) -> Result<(), Box<dyn Error>> {
  match is_stdin_piped() {
    true => piped_grep(PipedGrepOptionsBuilder::parse(args)?)?,
    false => grep(GrepOptionsBuilder::parse(args)?)?,
  }
  Ok(())
}

The following is an example of how to use readline():

use r3bl_rs_utils::utils::{
  print_header, readline, style_dimmed, style_error, style_primary, style_prompt,
};

fn make_a_guess() -> String {
  println!("{}", Blue.paint("Please input your guess."));
  let (bytes_read, guess) = readline();
  println!(
    "{} {}, {} {}",
    style_dimmed("#bytes read:"),
    style_primary(&bytes_read.to_string()),
    style_dimmed("You guessed:"),
    style_primary(&guess)
  );
  guess
}

Here's a list of functions available in this module:

readline_with_prompt()
print_prompt()
readline()
is_tty()
is_stdout_piped()
is_stdin_piped()

safe_unwrap

Functions that make it easy to unwrap a value safely. These functions are provided to improve the ergonomics of using wrapped values in Rust. Examples of wrapped values are <Arc<RwLock<T>>, and <Option>. These functions are inspired by Kotlin scope functions & TypeScript expression based language library which can be found here on r3bl-ts-utils.

Here are some examples.

use r3bl_rs_utils::utils::{
  call_if_some, unwrap_arc_read_lock_and_call, unwrap_arc_write_lock_and_call, with_mut,
};
use r3bl_rs_utils::utils::{ReadGuarded, WriteGuarded};
use r3bl_rs_utils::{
  arena_types::HasId, ArenaMap, FilterFn, NodeRef, ResultUidList, WeakNodeRef,
};

if let Some(parent_id) = parent_id_opt {
  let parent_node_arc_opt = self.get_node_arc(parent_id);
  call_if_some(&parent_node_arc_opt, &|parent_node_arc| {
    unwrap_arc_write_lock_and_call(&parent_node_arc, &mut |parent_node| {
      parent_node.children.push(new_node_id);
    });
  });
}

Here's a list of functions that are provided:

call_if_some()
call_if_none()
call_if_ok()
call_if_err()
with()
with_mut()
unwrap_arc_write_lock_and_call()
unwrap_arc_read_lock_and_call()

Here's a list of type aliases provided for better readability:

ReadGuarded<T>
WriteGuarded<T>

color_text

ANSI colorized text https://github.com/ogham/rust-ansi-term helper methods. Here's an example.

use r3bl_rs_utils::utils::{
  print_header, readline, style_dimmed, style_error, style_primary, style_prompt,
};

fn make_a_guess() -> String {
  println!("{}", Blue.paint("Please input your guess."));
  let (bytes_read, guess) = readline();
  println!(
    "{} {}, {} {}",
    style_dimmed("#bytes read:"),
    style_primary(&bytes_read.to_string()),
    style_dimmed("You guessed:"),
    style_primary(&guess)
  );
  guess
}