rust-hotswap

A library for hotswapping running code with minimal effort.

Beware that the library is a completely unsafe prototype for now, and it will probably crash a lot.

Usage

• Using a nightly rust, import the plugin hotswap.
• Annotate the functions you want to hotswap with the #[hotswap] modifier.
• Add the #![hotswap_header] to the top of your program.
• Add the hotswap_start!() macro to the entry point of your program, before you call any hotswapped functions.

Current Limitations

• Changing hotswapped function signatures WILL result in a segfault.
• Requires extra dependency in the user application.
• Leaks a dynamic library on each swap.

Example

```toml

Cargo.toml

[package] name = "hotswapdemo" version = "0.1.0"

[lib] name = "hotswapdemo" crate-type = ["dylib"] path = "src/main.rs"

[dependencies] hotswap = "" # libloading is a required libloading = "" # dependency for now ```

```rust // main.rs

![feature(plugin)]

![plugin(hotswap)]

![hotswap_header]

use std::thread::sleep; use std::time::Duration;

[hotswap]

fn test(test: i32) -> () { println!("Foo: {}", test); }

fn main() { hotswap_start!();

loop {
    test(123);
    sleep(Duration::from_millis(2000));
}

}

```

And that is it! From there you can ```

cargo run Running target\debug\hotswaptest.exe Foo: 123 Foo: 123 Foo: 123 ```

and if you edit the printing code, changing it to rust println!("Bar: {}", test); and recompiling the code on another terminal (or putting the running task in the background) ```

cargo build --lib Compiling hotswapdemo v0.1.0[...] fg Foo: 123 Foo: 123 Bar: 123 Bar: 123 ``` the running function will update automatically to the latest version without restarting the executable!