EFX — Rust templating for egui/eframe

EFx

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EFx — Rust 🦀 XML Template Engine for egui-based frameworks: eframe, bevy_egui, egui-winit, egui-miniquad. efx! is a proc-macro for writing tiny XML-like UI snippets in eframe/egui. It converts short tags into egui calls.

Simplicity and Convenience — XML, 🚀 Speed and 🔐 Security — Rust

Easy as HTML, Fast as C

You can embed arbitrary Rust expressions inside braces ({...}).

Install & import

Requires egui (the project currently uses egui 0.32). Add to Cargo.toml:

[dependencies]
efx = "0.6"
egui = "0.32" # or egui-based framework

Inside this repo just import the macro:

use efx::efx; // the macro

Documentation

You can see on web page https://docs.rs/efx/latest/efx/ or in files:

Expression interpolation `{...}`

Inside tag content you can insert any Rust expression that implements Display:

let a = 2;
let b = 3;
efx!(ui, r#"<Label>Sum: {a + b}</Label>"#);

Escaping braces

To print { or }, use double braces (same as format!):

efx!(ui, r#"<Label>Literals: {{ and }}</Label>"#);

Errors & diagnostics

At compile time the macro parses your snippet; at runtime it shows readable diagnostics via ui.Label(...) when input is invalid:

Unknown tag Output: Unknown tag: <TagName>
Mismatched open/close tags Output: Mismatched tags: <open> and </close>
Interpolation count mismatch Happens if the parser found e.g. two {expr} parts but after processing the text there’s a different number of {} placeholders. Make the counts match.

Current limitations

Case-sensitive tag names.
Interpolated expressions must implement Display.

Roadmap & RFCs

TL;DR. EFx is a minimalist XML DSL on top of egui that compiles to plain ui.* calls. The next three releases focus on expressiveness and first-class examples across popular egui runtimes:

0.7 — Themes & layouts: lightweight style sheets, extended containers (Tabs/Table behind extras), perf & polish.

This plan is incremental and non-breaking; new features are opt-in. Priorities may change based on community feedback.

👉 Full RFC: EFX-0001 — Roadmap 0.5–0.7

👉 RFC index: RFC/README.md

Supported `egui` runtimes

EFx renders into any runtime that provides &mut egui::Ui. We officially build examples for the following targets:

Tier-1

eframe (native + wasm)
bevy_egui (native)
raw winit+wgpu (via egui-winit + egui-wgpu). Wgpu - a cross-platform, safe, pure-rust graphics API. It runs natively on Vulkan, Metal, D3D12, and OpenGL; and on top of WebGL2 and WebGPU on wasm. Follows WebGPU specification. With async/await API.

Tier-2 (compatible today; examples later / community support)

egui-miniquad (for macroquad/miniquad overlays) - Relatively minimalistic API well suited for small to medium graphics projects. Supports multiple backends, including browser target.
egui_sdl2_* backends
egui_glow / tao (lower-level backends)

Quickstart (pick one)

A) eframe

# Cargo.toml
[dependencies]
efx    = "0.6"
eframe = "0.32"

use eframe::egui;
use efx::efx;

egui::CentralPanel::default().show(ctx, |ui| {
    efx!(ui, r#"<Column><Label>Hello, EFx</Label><Separator/></Column>"#);
});

B) Bevy + bevy_egui

# Cargo.toml
[dependencies]
efx       = "0.6"
bevy      = "0.16"
bevy_egui = "0.36"  # re-exports `egui`

use bevy_egui::{EguiPlugin, EguiContexts};
use efx::efx;

bevy_egui::egui::Window::new("EFx").show(egui_ctx.ctx_mut(), |ui| {
    efx!(ui, r#"<Row><Label>It works</Label></Row>"#);
});

Tip: import egui via use bevy_egui::egui as egui; to avoid version mismatches.

C) Raw winit + wgpu

# Cargo.toml
[dependencies]
efx        = "0.6"
egui       = "0.32"
egui-winit = "0.32"
egui-wgpu  = "0.32"
winit      = "0.30"
wgpu       = "26.0"

Use the example in examples/winit_wgpu_min.rs as a starting point.

Contributing

Thanks for considering a contribution! Please follow this lightweight workflow:

1) Pick or propose an issue

Claim an issue: comment “I’d like to take this” (optionally add a brief plan/ETA). The maintainer will assign it to you.
Propose a new issue: open a ticket with a minimal reproducible example (for bugs) or a short rationale (for features). Start with the roadmap RFC: EFX-0001.

Tip: issues labeled good first issue are designed for first-time contributors.

2) Fork & branch

Fork the repository and create a feature branch from main:

git checkout main
git pull
git checkout -b feat/short-topic

Keep your branch focused on one issue.

3) Implement with tests & docs

Make the change and add tests/docs where it makes sense.

Local checks (examples build-only; no GUI run is required):

cargo fmt --all
cargo clippy --all-targets -- -D warnings
cargo build --workspace --locked
cargo build -p efx --example eframe_demo --locked
rustup target add wasm32-unknown-unknown
cargo build -p efx --example eframe_demo --target wasm32-unknown-unknown --locked

4) Open a Pull Request

Target the next release branch (e.g., v0.6, v0.7). If the issue has a milestone, use the branch named after that milestone.
Link the issue (e.g., “Closes #123”) and fill the checklist below.

PR checklist

References the related issue / RFC section when behavior changes.
CI is green (workspace build, examples, wasm32 build-only).
Tests/docs updated where applicable.
No unrelated changes.

5) Reviews & merge

Address review comments; small, focused PRs get merged faster.
If you go silent for 7 days, the issue may be unassigned to keep momentum (you can re-claim it anytime).

Questions? Reach out at mail@zhukmax.com.

Changelog

See in file Changelog.md

Licence

The MIT License. Please see License File for more information.

efx 0.6.1

EFx