morphix 0.1.0

Mutate and observe Rust data structures
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# morphix

[![Crates.io](https://img.shields.io/crates/v/morphix.svg)](https://crates.io/crates/morphix)
[![Documentation](https://docs.rs/morphix/badge.svg)](https://docs.rs/morphix)
 
A Rust library for observing and serializing changes.

## Installation

Add this to your `Cargo.toml`:

```toml
[dependencies]
morphix = { version = "0.1" }
```

## Basic Usage

```rust
use serde::Serialize;
use serde_json::json;
use morphix::{Change, JsonAdapter, Observe, Operation, observe};

// 1. Define any data structure with `#[derive(Observe)]`.
#[derive(Serialize, PartialEq, Debug, Observe)]
struct Foo {
    pub bar: Bar,
    pub qux: String,
}

#[derive(Serialize, PartialEq, Debug, Observe)]
struct Bar {
    pub baz: i32,
}

let mut foo = Foo {
    bar: Bar { baz: 42 },
    qux: "hello".to_string(),
};

// 2. Use `observe!` to mutate data and track changes.
let change = observe!(JsonAdapter, |mut foo| {
    foo.bar.baz += 1;
    foo.qux.push(' ');
    foo.qux += "world";
})
.unwrap();

// 3. Inspect the changes.
assert_eq!(
    change,
    Some(Change {
        path_rev: vec![],
        operation: Operation::Batch(vec![
            Change {
                path_rev: vec!["baz".into(), "bar".into()],
                operation: Operation::Replace(json!(43)),
            },
            Change {
                path_rev: vec!["qux".into()],
                operation: Operation::Append(json!(" world")),
            },
        ]),
    }),
);

// 4. The original data structure is also mutated.
assert_eq!(
    foo,
    Foo {
        bar: Bar { baz: 43 },
        qux: "hello world".to_string(),
    },
);
```

## Change Types

morphix recognizes three types of changes:

### Replace

The most general change type, used for any mutation that replaces a value:

```rust ignore
person.age = 35;                // Replace at path .age
person.name = "Bob".into();     // Replace at path .name
```

### Append

Optimized for appending to strings and vectors:

```rust ignore
person.name.push_str(" Smith");         // Append to .name
person.hobbies.push("gaming".into());   // Append to .hobbies
```

### Batch

Multiple changes combined into a single operation.

## Features

- `derive` (default): Enables the Observe derive macro
- `json` (default): Includes JSON serialization support via serde_json