Live code reloading
volt supports live code reloading, which makes it perfect for developing scientific applications and games:

About the language volt is written in

Originally volt was written in Go, but after a couple of weeks of development I decided to re-write it in C for two reasons: easier integration with existing C graphics and UI libraries and much smaller and lighter binaries. The app size reduced from ~5 MB to ~100 KB.

C development is not very productive, so I spent two weeks in October 2017 to create a very light and minimalistic language that compiles to C. I haven't come up with a name yet, so I simply call it volt for now.

The language will be open-sourced later in 2018. The key features are:

Fast compilation
The entire volt project (~15 kloc) is compiled in ~400ms.

volt is very similar to Go in this regard. There's only one of way of doing things.

High performance
volt is compiled to C with no added overhead, so the performance is the same.

Variables are immutable by default, globals are not allowed, functions are partially pure (only receivers can be modified).

Here's a Hello World GUI example:

package main

import 'ui' 

type Context struct {
    input *ui.TextBox

fn main() {
    mut wnd := ui.new_window(ui.WindowCfg{
        width: 600,
        height: 300,
        title: 'hello world',
    ctx := &Context{
        input: ui.new_textbox(wnd), 
    ctx.input.set_placeholder('Enter your name')
    btn := ui.new_button(wnd, 'Click me', btn_click)

fn btn_click(parent *ui.Window) {
    ctx := parent.user_ptr.(*Context) 
    name := ctx.input.text()
    ui.alert('hello, $name!')