Doublets

A library that represents database engine that uses doublets.

Overview

Example

A basic CRUD in doublets

```rust use doublets::{ data::Flow::Continue, mem::FileMappedMem, unit, Doublets, Error }; use std::fs::File;

fn main() -> Result<(), Error> { // create or open read/write file let file = File::options() .create(true) .read(true) .write(true) .open("db.links")?;

let mem = FileMappedMem::new(file)?;
let mut links = united::Store::<usize, _>::new(mem)?;

// Creation of the empty doublet in tiny style
let mut point = links.create()?;

// Update of the doublet in handler style
// The link is updated to reference itself twice (as source and target):
links.update_with(point, point, point, |_, after| {
    // link is { index, source, target }
    point = after.index;
    // give handler state (any ops::Try)
    Continue
})?;

// print all links from store
links.each(|link| {
    println!("{link}");
    Continue
});

// The link deletion in full style:
// `any` constant denotes any link
let any = links.constants().any;
// query in [index source target] style
// delete all links with index = point
links.delete_by_with([point, any, any], |before, _| {
    println!("Goodbye {}", before);
    Continue
})?;
Ok(())

} ```