public/subjects/get_document_id

get_document_id

Instructions

Create the following structures which will help you get the document_id of the document you need.

• OfficeOne: next_office as type Result<OfficeTwo, ErrorOffice>.
• OfficeTwo: next_office as type Result<OfficeThree, ErrorOffice>.
• OfficeThree: next_office as type Result<OfficeFour, ErrorOffice>.
• OfficeFour: document_id as type Result<u32, ErrorOffice>.

ErrorOffice is an enum with OfficeClosed(u32), OfficeNotFound(u32) or OfficeFull(u32).

The u32 is the id of the office generating the error.

Beside the structures, you must create a function named get_document_id, and associate it to the OfficeOne structure.

This function should return the Result value in the OfficeFour structure or the first Err it finds in the chain.

Expected Function and structures

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum ErrorOffice {
    OfficeClose(u32),
    OfficeNotFound(u32),
    OfficeFull(u32),
}

#[derive(PartialEq, Eq, Clone, Copy)]
pub struct OfficeOne {
    pub next_office: Result<OfficeTwo, ErrorOffice>,
}

#[derive(PartialEq, Eq, Clone, Copy)]
pub struct OfficeTwo {
    pub next_office: Result<OfficeThree, ErrorOffice>,
}

#[derive(PartialEq, Eq, Clone, Copy)]
pub struct OfficeThree {
    pub next_office: Result<OfficeFour, ErrorOffice>,
}

#[derive(PartialEq, Eq, Clone, Copy)]
pub struct OfficeFour {
    pub document_id: Result<u32, ErrorOffice>,
}

impl OfficeOne {
    pub fn get_document_id(&self) -> Result<u32, ErrorOffice> {}
}

Usage

Here is a program to test your function.

use get_document_id::*;

fn main() {
    let office_ok = OfficeOne {
        next_office: Ok(OfficeTwo {
            next_office: Ok(OfficeThree {
                next_office: Ok(OfficeFour {
                    document_id: Ok(13),
                }),
            }),
        }),
    };
    let office_closed = {
        OfficeOne {
            next_office: Ok(OfficeTwo {
                next_office: Err(ErrorOffice::OfficeClose(23)),
            }),
        }
    };

    match office_ok.get_document_id() {
        Ok(id) => println!("Found a document with id {}", id),
        Err(err) => println!("Error: {:?}", err),
    };
    match office_closed.get_document_id() {
        Ok(id) => println!("Found a document with id {}", id),
        Err(err) => println!("Error: {:?}", err),
    };
}

And its output:

$ cargo run
Found a document with id 13
Error: OfficeClose(23)
$