Debt

Debt

One of the greatest ways to learn a new language is making a new project, today I want to share with you one toy application made in rust. It is a simple CLI debt manager.

How to use it

Thanks to clap the design of its CLI was pretty straightforward, it has a must have feature I always look since I met docopt (from python), that is documentation integrated with the functional design:

Usage: debt [OPTIONS] <COMMAND>

Commands:
  init      Initialize Database
  register  Register a transaction
  view      View Registered data
  add       Add a new agent to lend or pay
  help      Print this message or the help of the given subcommand(s)

Options:
  -d, --database-path <DATABASE_PATH>  file path where data is stored [default: $XDG_DATA_HOME/debt/debt.db [env: DEBT_DB=]
  -h, --help                           Print help
  -V, --version                        Print version

Examples

Putting examples ease a lot the process of explaining a new user how to use a CLI tool, so below you have the necessary ones to learn use my program.

Initialize a debt database:

$ debt init

Add a new debtor:

$ debt add 'Jane Doe'

Borrow 1000 (dollars, euros or whatever) to Jane Doe:

$ debt register 'Jane Doe' 1000 'Some optional note'

Register a payment of 50 (of any exchange) from Jane Doe:

$ debt register -p 'Jane Doe' 50 'Another optional note'

View the people who owes you money.

$ debt view

Checkout payments and loans history:

$ debt view -H

Filter Jane Doe history

$ debt view -H 'Jane Doe'

How it works

It is basically a CLI programs that manages the database presented below using rusqlite.

CREATE TABLE Agents (
    id INTEGER PRIMARY KEY,
    name TEXT NOT NULL UNIQUE
    )

CREATE TABLE Registers (
    id INTEGER PRIMARY KEY,
    agent_id INTEGER,
    register_date INTEGER NOT NULL,
    amount INTEGER NOT NULL,
    note TEXT,
    FOREIGN KEY(agent_id) REFERENCES Agents(id)
    )

What I learnt

Let me list you some of the things clarified to me while making this project:

• The difference between &str and String data types.
• How to work with Files.
• The point of Option and Result generic types, and why is common to see methods like unwrap or expect.
• Have a better idea of variable lifetimes.
• How to create modules in rust.
• Have a better sense of ownership and the borrow checker.
• A little about how to use macros.
• The difference between Path and Pathbuf.

Checkout the repo:

Feel free to clone my repo or check the source code here