# Error management
Chained error management, built-in functions, no extra features required.
## Usage
> **Tips**: you can easily implement your own `Error` type.
```rust
use ruc::{err::*, *};
#[derive(Debug, Eq, PartialEq)]
struct CustomErr(i32);
fn will_panic() {
let l1 = || -> Result<()> { Err(eg!("The final error message!")) };
let l2 = || -> Result<()> { l1().c(d!()) };
let l3 = || -> Result<()> { l2().c(d!("A custom message!")) };
let l4 = || -> Result<()> { l3().c(d!("ERR_UNKNOWN")) };
let l5 = || -> Result<()> { l4().c(d!("{:?}", CustomErr(-1))) };
pnk!(l5());
}
```
## Output Sample
#### Non-Color View
> without the `ansi` feature (e.g. `--no-default-features`)
```
# 2021-09-09 09:23:56 +08 [pid: 20837] [pidns: 4026531836]
ERROR: ...
|-- file: src/lib.rs
|-- line: 270
`-- column: 9
Caused By: ...
|-- file: src/lib.rs
|-- line: 264
`-- column: 16
Caused By: CustomErr(-1)
|-- file: src/lib.rs
|-- line: 262
`-- column: 44
Caused By: ERR_UNKNOWN
|-- file: src/lib.rs
|-- line: 261
`-- column: 44
Caused By: A custom message!
|-- file: src/lib.rs
|-- line: 260
`-- column: 44
Caused By: ...
|-- file: src/lib.rs
|-- line: 259
`-- column: 69
Caused By: The final error message!
|-- file: src/lib.rs
|-- line: 258
`-- column: 41
```
#### Colorful View
> features = ["ansi"] (enabled by default)
```
# 2021-09-09 09:23:57 +08 [pid: 20909] [pidns: 4026531836]
ERROR: ...
├── file: src/lib.rs
├── line: 270
└── column: 9
Caused By: ...
├── file: src/lib.rs
├── line: 264
└── column: 16
Caused By: CustomErr(-1)
├── file: src/lib.rs
├── line: 262
└── column: 44
Caused By: ERR_UNKNOWN
├── file: src/lib.rs
├── line: 261
└── column: 44
Caused By: A custom message!
├── file: src/lib.rs
├── line: 260
└── column: 44
Caused By: ...
├── file: src/lib.rs
├── line: 259
└── column: 69
Caused By: The final error message!
├── file: src/lib.rs
├── line: 258
└── column: 41
```
#### Compact View
> shown with `--no-default-features --features compact`
```
# 2022-01-12 05:56:13 +08 [pid: 73002] [pidns: NULL] 》INFO: ... 》file: src/lib.rs 》line: 354 》column: 9 》Caused By: ... 》file: src/lib.rs 》line: 354 》column: 33
```