This is a set of macros for ergonomically working with TCells and TLCells from the qcell crate. This is particularly inspired by the cell_family crate, and one additional goal for the cell_wrappers crate is to be compatible with the qcell codebase as a dependency; no forking necessary.

Simple declaration

Creating a marker-owner-cell system is easy with def_cells, as we can see here:

def_cells! {
    [pub mod] foo_grp: TCellUniGrp;
}

This creates a new inline module (named foo_grp, in this example), and populates it with a new TCell system, along with some automatically-implemented traits that will help other parts of this crate provide you with even more leverage.

You can even create complex clusters of systems in one go:

def_cells! {
    [pub mod] put_some_here::{a_bit_further: TLCellUniGrp};
    [pub mod] two_go_here::{
        this_longer_way::{now_arrived: TLCellPvtGrp},
        and_also_this_way: TLCellPubGrp
    };
    [mod] oh_and_here_too::{no_here::{okay_yes_here: TLCellAccGrp}};
}

The above declaration will create the following inline modules of cell systems:

pub mod put_some_here {
    pub mod a_bit_further { ... }
}
pub mod two_go_here {
    pub mod this_longer_way {
        pub mod now_arrived { ... }
    }
    pub mod and_also_this_way { ... }
}
mod oh_and_here_too {
    pub mod no_here {
        pub mod okay_yes_here { ... }
    }
}

The following types were also declared in put_some_here::a_bit_further, for example, since we declared it as a TLCellUniGrp:

pub mod put_some_here {
    pub mod a_bit_further {
        // This is a TLCell Uni Grp (or "TLCellUniGrp"):
        pub struct UniMarker;
        pub type UniCell<T> = qcell::TLCell<UniMarker,T>;
        pub type UniOwner = qcell::TLCellOwner<UniMarker>;

        // Utility traits are implemented too:
        // ...
    }
}

Cell system subcategories

This crate also offers four subcategories of cell systems, which offer three subcategories of cells, primarily for self-describing project organization purposes.

The subcategories of cells are:

1. uniform: A general-purpose subcategory
2. private: A subcategory intended for private struct methods
3. public: A subcategory intended for program-wide use

The mod subcategories are:

1. UniGrp: Creates one system of uniform cells
2. AccGrp: Creates one system of public cells, and one system of private cells
3. PubGrp: Creates one system of public cells
4. PvtGrp: Creates one system of private cells

And these get appended to the cell types to form declaration identifiers, like so:

TLCell + UniGrp -> TLCellUniGrp

Families-style declaration:

Before explaining the benefits of these subcategories, this crate does also provide even simpler declarations for anyone who prefers the simplicity of cell_family. The cell_wrappers crate only depends on the qcell implementation, however, and does not reimplement the same logic adjustments found in the cell_family implementation.

// For creating a TCell system:
new_t_group!(FooOwner[FooMarker] => FooCell<T>);

// An alternative syntax, and creating a TLCell system this time:
new_tl_group! {
    marker: BarMarker,
    owner: BarOwner,
    cell: BarCell<T>
}

// And if you'd rather create each part individually:
new_t_marker_type!(BazMarker);
new_t_cell_type!(BazCell[BazMarker]<T>);
new_t_owner_type!(BazOwner[TestTMarker]);

// These allows for visibility specs and attributes:
new_t_group!(#[allow(dead_code)] pub FooOwner[FooMarker] => FooCell<T>);

new_tl_group! {
    pub marker: BarMarker,
    #[allow(dead_code)]
    pub owner: BarOwner,
    pub cell: BarCell<T>
}

Read more at:

• new_t_group / new_tl_group
• new_t_marker / new_tl_marker
• new_t_owner / new_tl_owner
• new_t_cell / new_tl_cell

Quick owner scopes

This crate provides a flexible macro-based syntax for quickly and easily setting up cell owner scopes for a wide variety of use cases.

This macro is called "c_scp", which is short for "cell scope".

The following is an example, which will be investigated shortly:

c_scp! {
    use test_uni_grp::UniOwner => (
        self.test_cell => mut test_cont
    ) {
        *test_cont += 1;
        assert_eq!(*test_cont, 1);
    }
}

Owner reference

We start by declaring the owner type to use, and we will create an anonymous one: \

use test_uni_grp::UniOwner =>

However, we also have these options, too:

1. let owner_name = test_uni_grp::UniOwner =>
   Owners default to the name "__scope_owner", but we can also set a custom name, such as owner_name.
2. use _ => or let owner_name = _ =>
   This automatically determines the necessary owner type, based on context.
3. use [self] => or let owner_name = [self] =>
   This can only be used in the method of a struct, which implements one of three special traits, and will be explained in more detail later.
4. use &borrowed_owner => or use &mut borrowed_owner =>
   This selects an owner available in the surrounding scope, declared with the identifier of borrowed_owner, for example.

Cell and container references

Next, we have the following: \

(self.test_cell => mut test_cont)

This selects self.test_cell as the cell which matches the owner, and its contained value will be assigned to a new variable, called test_cont. We are declaring test_cont as mutable here, so the owner will be borrowed mutably, too, and the cell will be accessed with its rw() method.

If we only wanted to select the cell, and not access it yet, then the syntax lets us work with the following alternatives:

1. (self.test_cell)
   which coerces the owner to be borrowed immutably, and...

2. (mut self.test_cell)
   ...which coerces the owner to be borrowing mutably.

Container reference options

There are quite a lot of ways to declare the container variable:

1. (self.test_cell => test_cont)
   Declares an immutable variable.

2. (self.test_cell => & test_cont)
   Adds an extra borrow operator when pulling self.test_cell's value.

3. (self.test_cell => * test_cont)
   Dereferences the value within self.test_cell before assigning it to test_cont.

4. (self.test_cell => *mut test_cont)
   Dereferences the value first, but also declares test_cont as mutable.

5. (self.test_cell => *out outer_cont)
   Dereferences the value in self.test_cell, and assigns it to a variable found in the surrounding scope, which is called outer_cont, in this example. This is useful for situations where you do not want to work with the value in a new scope, and just want to extract the value from the cell for use in the surrounding scope.

6. (self.test_cell => *out mut test_cont)
   Same as before, but for cases where outer_cont is declared mutable.

7. (self.test_cell => test_cont : u8)
   Coerces the extracted value to u8 before storing it in test_cont.

8. (self.test_cell => *out test_cont as u8)
   When sending the value to the surrounding scope, as must be used, since a new variable is not being declared for use in the inner scope.

Scope body

Finally, we have...

{ *test_cont += 1; assert_eq!(*test_cont, 1); }

...which is just the statement block that gets put into the new enclosing scope. Once these are completed, then the scope is exited, and the owner will be dropped, unless it was borrowed from an outer scope.

Provided utility traits

This crate provides a lot of traits for internal use, but three of them are available for you to make use of, specifically:

// 1.
pub trait GetPvtOwner<T> {
    fn get_private_owner(&self) -> T;
}

// 2.
pub trait GetPubOwner<T> {
    fn get_public_owner(&self) -> T;
}

// 3.
pub trait GetUniOwner<T> {
    fn get_uniform_owner(&self) -> T;
}

For c_scp syntaxes which use the [self] owner source, these traits are called for self. A struct can implement these for any number of relevant owners, and three macros are provided for automatic implementation of these traits:

1. impl_get_pvt!(struct_name, owner::Path);
2. impl_get_pub!(struct_name, owner::Path);
3. impl_get_uni!(struct_name, owner::Path);

You may also want to create custom implementations for these, as well, in case you want these methods to do any extra tasks before or after an owner is being provided.

These three traits are selected by the cell being accessed in the c_scp syntax, so it will choose a uniform, public, or private implementation based on its own declared subcategory type.

Read more at:

• GetPvtOwner / impl_get_pvt
• GetPubOwner / impl_get_pub
• GetUniOwner / impl_get_uni