RailsGun

RailsGun or Railgun, call it how you want it. This crate add a lot of small but usefull functionality to the existing Rail paradigm in rust.

If you are used to use rails in rust, you know what its all about! If its the first time you hear about it I would highly suggest you to read the following Railway Oriented Programming; In short its a programming style that I have found over multiple project and services to reduce the errors.

This crate supplies you with some extra missing tools and simplifications as follows:

tap, tap_err, tap_ref, tap_err_ref

This is a nice little trait that adds the ability to "tap" the contents. This means that you can get a copy/clone of the original content that you can use for analysis or other destructive operations without actually touching the original.

Note: tap_ref and tap_err_ref unfortunatly is just a reference so destructive actions should not be taken.

merge, merge2, merge3, merge4

This is for merging multiple results. If you have worked with rails before you have probably tried the following:

x.and_then(|var_x|  
    y.and_then(|var_y|
        z.and_then(|var_z|
            func_xyz(var_x, var_y, var_z)
        )
    )
)

This is a very ugly method of combining 3 results, you could split it out in multiple functions, but at times that is very excessive. Merge supplies you with a nice functionality for this.

x.merge2(y, z, |var_x, var_y, var_z| func_xyz(var_x, var_y, var_z)

As you can see this simplifies the rail significantly and makes it more readable/maintainable.

Trait BlockInPlaceResult

This is a trait that requires your system to currently be running inside a Tokio thread as it requires multithreading. That said it adds some interesting capabilities on top of the result. If the following annoys you:

async fn my_async_fn() -> Result<&str, &str> {
    Ok("Something awesome")
}
my_async_fn.await.and_then(|t| println!("{}", t))

This allows you to cut corners by:

async fn my_async_fn() -> Result<&str, &str> {
    Ok("Something awesome")
}
my_async_fn.and_then(|t| println!("{}", t))

Please note this is using tokios block_in_place for execution

AsyncResult

As the name describes, this is an AsyncResult. It has almost everything that a Result has, and some other extra features. This allows you to execute async functions and code inside your rail by doing the following

async fn do_something(t: &str) -> AsyncResult<&str,&str> {
    t
}

x.and_then(|t| do_something(t)).await
    .and_then(|t| async move { t }).await;

Of course this is not the prettiest thing, but it allows the system to keep to its rail and keep processing without moving in and out of the rails.

Of course this also comes with From/Into implementations for Result and even a into_async/into_sync implementation that is more descriptive when converting between AsyncResult and Result

ToDo

There is a significant need for more documentation on the trait and others as this library has been in my private stack for a long time and did get the doc-care it needed.

tap needs doc
merge needs doc
Implement BlockInPlace for AsyncResult

Please open a ticket for more ideas!

Contribution

Feel free to contribute to the project. Currently the project is hosted on both GitHub and my private GitLab. The main repository is the GitLab repository where all of the pipelines and all of my projects exists.

License

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

railsgun 0.1.3