Crate utils_results

First, You should make your own an error set.

Example

err! {
     BrokenHeader => "broken header."
     AnotherHeader => "not matched header."
     FileNotFound => "file not found."
     EmptyArgument => "empty argument."
     UnexpectedEof => "unexpected eof."
     OutOfBounds => "index out of bounds."
     NotMatched => "btw not matched."
}

And just errbang!

errbang!(err::BrokenHeader);

More Examples

fn foo() -> Result<bool> { // Our Master Result Type
    let bar = 2;
    match bar {
        0 => Ok(true),
        1 => Ok(false),
        _ => errbang!(err::NotMatched, "{} is {}", "bar", bar),
    }
}
fn main() -> Result<()> {
    let _is_bar_zero = foo()?;
    Ok(())
}

errbang!(err::MyError1);
errbang!(err::MyError2, "cannot find.");
errbang!(err::MyError3, "{} is {}", "bar", 2);

| Result

[src/main.rs 40:1] unexpected eof. bar is 2 <err::UnexpectedEof>

Important

utils-results can handle lots of errors in a beautiful one way.
It’s called Non panic unwraping chaining Errors.
errbang -> errcast -> errcast -> … -> errcast -> errextract

Quick Overview

use utils_results::*;

err! {
    One => "this error is first one."
    Two => "this error is second one."
    Three => "this error is third one."
    Well => "is this?"
}


fn aaa() -> Result<usize> {
    return errbang!(err::One, "{}.error bang!", 1);
}

fn bbb() -> Result<usize> {
    let n = errcast!(aaa(), err::Two, "{}.two <- one.", 2);
    Ok(n)
}

fn ccc() -> ResultSend<usize> { // Result -> ResultSend
    Ok(errcast!(bbb(), err::Three, "{}.three <- two.", n))
}


fn main() -> Result<()> {
    let c = errextract!(ccc(), err::Well => 127);
    eprintln!("1/{} is cosmological constant.", c);
    Ok(())
}

| Result

Error:
[src/main.rs 11:12] this error is first one. 1.error bang! <err::One> aaa()
                    ⎺↴
[src/main.rs 14:13] this error is second one. 2.two <- one. <err::Two> bbb()
                    ⎺↴
[src/main.rs 18:8] this error is third one. 3.three <- two. <err::Three>

If the matching error be changed,

// Well to Three
let c = errextract!(ccc(), err::Three => 127);

| Result

1/127 is cosmological constant.

---

errcast

Any type of error can be converted into our Master Error. (non panic unwraping)

// example
// <Unwraped Ok> = errcast!(<Any Result>, <Master Err>, <Optional,..>);
let num_read = errcast!(file.read(&mut buf), err::ReadErr, "this is {} data.", "meta");

---

Simply just do this!

let file = errcast!(File::open("test"), err::FileOpenError)

or…

// master `Result` can take any errors
let file = File::open("test")?;

But, errcast -> errextract combo is always good choice.

fn exe(path: &str) -> Result<usize> {
    let file = errcast!(File::open("test"), err::FileOpenError);
    // .....
    // ...
    Ok(num)
}

fn main() -> Result<()> {
    /// non panic unwraping
    /// and specific error can return
    /// matching block
    let num = errextract!(exe(path),
        err::FileOpenError => 0);
    /// other errors will go out -> Result<T>

    Ok(())
}

---

Well, we can also handle io::Error more idiomatic way.

Matching io::Error

 io_err! {
     // io::ErrorKind => err::MyError
     UnexpectedEof => err::MyError1
     Interrupted => err::MyError2
     NotFound => err::MyError3
     // ...
 }

Declare matching macro and just handle that!

io_to_err!(file.seek(SeekFrom::End(0)))?;

err_to_io!(my_seek(0))?;

Master Result

• Please use our Master Result<T> and ResultSend<T> instead std::result::Result or io::Result etc..

---

utils-results/lib.rs Definition

/// Master Result
pub type Result<T> = result::Result<T, Box<dyn error::Error>>;

/// Master Result for Send + Sync trait
pub type ResultSend<T> = result::Result<T, Box<dyn error::Error + Send + Sync>>;

---

just put this in your project.

pub use utils_results::*;

You can also convert any type of Result

// to our Master Result
resultcast!(handle.join().unwrap())?;
// to our Master ResultSend
resultcastsend!(handle.join().unwrap())?;

Macros

err

create custom error list

err_to_io

casting Master Error to std::io Error matched by io_err

errbang

make some error. floating Err(..)

errcast

Any type of error can be converted into our Master Error. (non panic unwraping)

errextract

non panic unwraping and specific error can return matching block
other errors will go out -> Result<T>

errmatch

any type of inside Err() can match this

io_err

matching io::Error and Master Error to use casting error macros

io_to_err

casting std::io Error to Master Error matched by io_err

resultcast

this will convert any result type to Master Result.

resultcastsend

this will convert any result type to Master ResultSend.

Type Definitions

Result

Master Result

ResultSend

Master Result for Send + Sync trait