v0.1.0 · early preview早期预览
SwiftUI, WinUI 3, GTK 4, Jetpack Compose and the Web, from one ui!. No JS engine and no embedded browser on the desktop or the phone; every button is an MCP tool an AI can call.
SwiftUI、WinUI 3、GTK 4、Jetpack Compose 与 Web，出自同一份 ui!。桌面和手机上没有 JS 引擎，没有内嵌浏览器；每个按钮，天生就是 AI 能调用的 MCP 工具。
cargo binstall bern-cli
#[component]
pub fn counter_view(app: counter::Client) -> impl View {
ui! {
Form {
Text(content: tr! {
"zh-Hans" => "已计数 {n} 次",
"en" => "Counted {n} times";
n: app.count
})
Button(id: add, label: tr! {
"zh-Hans" => "加一",
"en" => "Add one"
}) => app.add(1)
}
}
}
// → SwiftUI · WinUI 3 · GTK 4 · Compose · DOM01 / native
One controls_page declaration on every platform. Every switch, slider and sidebar is the platform's standard control, in the platform's own colors.
同一份 controls_page 声明，跑在每个平台上。每个开关、滑块和侧边栏都是平台自己的标准控件，用的是平台自己的配色。
02 / built for AI
AI rarely gets interface code wrong; it leaves things out. Elsewhere those wait for a user to find them. In Bern they do not compile, and the error says where, so an agent fixes it and builds again. AI 写界面很少写错，常常写漏。在别的框架里，要等用户自己撞上；在 Bern 里它们过不了编译，错误写清在哪里，Agent 改完直接再编。
$ bern check
error[B102]: Missing translation
Missing language: en
Required languages: zh-Hans, en
--> showcase-ui/src/pages.rs:13:31
$ bern check
error[B201]: Feature missing in adaptive layout
Contract: MediaFeature
Feature: Clip
compact: missing
--> showcase-ui/src/media.rs:14:5Every Bern app ships with a command line and an MCP server. Each control has a stable name and role; an agent reads the structure, acts through the same code path as a click, and the app answers with what actually happened. 每个 Bern 应用都自带命令行和 MCP 服务器。每个控件都有稳定的名字和角色；Agent 读的是结构，做的事和用户点击走同一段代码，结果由应用如实答复。
$ showcase ui inspect
[{ "target": "controls_page.sync", "role": "switch",
"label": "Sync", "value": "false", "enabled": true }, …]
$ showcase ui set-bool --target controls_page.sync --value true
$ showcase window close --window settings#1
{ "outcome": "ConfirmationRequired",
"message": "Do you want to save the display name?",
"decisions": ["Save", "Discard", "Cancel"] }03 / plain rust
A protocol declares the state and the commands; the engine implements them and never sees a window; the interface is a ui! declaration the compiler turns into each platform's code. The window, the command line and AI agents all drive the same engine.
协议声明状态和命令；引擎实现它们，看不到任何窗口；界面是一份 ui! 声明，由编译器生成每个平台的代码。窗口、命令行和 AI Agent 驱动的是同一个引擎。
#[bern::protocol(namespace = "counter", version = 1)]
pub mod counter {
use bern::prelude::*;
#[state]
pub struct State {
pub count: i64,
}
#[commands]
pub trait Commands {
/// Add to the count.
fn add(&mut self, by: i64) -> Result<(), CommandError>;
}
}pub struct Counter {
state: counter::State,
}
impl counter::Commands for Counter {
fn add(&mut self, by: i64) -> Result<(), CommandError> {
self.state.count += by;
Ok(())
}
}
impl counter::Engine for Counter {
fn state(&self) -> &counter::State {
&self.state
}
}#[component]
pub fn counter_view(app: counter::Client) -> impl View {
ui! {
Form {
Text(content: tr! {
"zh-Hans" => "已计数 {n} 次",
"en" => "Counted {n} times";
n: app.count
})
Button(
id: add,
label: tr! { "zh-Hans" => "加一", "en" => "Add one" },
prominence: prominent
) => app.add(1)
}
}
}$ counter ui inspect
$ counter ui activate --target counter_view.add
$ counter counter add --by 5
$ counter-mcp # the same catalog for AI agents04 / measured
The release showcase, median of at least 3 runs: Apple M4 · macOS 27, Intel i5-13490F · Windows 11. Hello World: a GitHub-hosted Apple M1, median of 10. The web app is 189 KB gzipped. 发布版展示应用，至少 3 次取中位数：Apple M4 · macOS 27，Intel i5-13490F · Windows 11。Hello World：GitHub 托管的 Apple M1，10 次取中位数。网页应用 gzip 后 189 KB。 benchmarks/ →
05 / built with bern
Local file sharing · compatible with LocalSend v2局域网文件传输 · 兼容 LocalSend v2
Device discovery, file and text transfers and receive approval, with one Rust codebase behind native SwiftUI, WinUI 3, GTK 4 and Jetpack Compose interfaces. 设备发现、文件与文字互传、接收确认，一套 Rust 代码，背后是原生的 SwiftUI、WinUI 3、GTK 4 与 Jetpack Compose 界面。
06 / get started
Rust 1.99, plus the toolchain of each platform you build: Xcode, Visual Studio, GTK, Android Studio. bern doctor tells you what is missing.
需要 Rust 1.99，以及要构建的平台各自的工具链：Xcode、Visual Studio、GTK、Android Studio。缺什么，bern doctor 会告诉你。
Ready-built for macOS, Windows and Linux; cargo install bern-cli compiles it instead.macOS、Windows、Linux 都有编译好的版本；也可以 cargo install bern-cli 自己编译。
$ cargo binstall bern-cliA window with a counter: a protocol, an engine and an interface crate.一个带计数器的窗口：协议、引擎、界面各一个 crate。
$ bern new my_app
$ cd my_appThis computer's platform by default, or any target you name.默认是这台电脑的平台，也可以指定目标。
$ bern run
$ bern run --target web_app
$ bern run --target android.dmg, Windows installer, .deb, .apk and .aab, and the web site, each with the app's CLI and MCP server..dmg、Windows 安装程序、.deb、.apk 与 .aab，以及网页，各自带上应用的命令行和 MCP 服务器。
$ bern package