emberc

emberc is a tiny C-to-WebAssembly (WAT) compiler written in Rust.

Supported Subset

• Types: int, unsigned int
• Variables: block-scoped local declarations with optional initialization
• Expressions:
  • arithmetic: + - * / %
  • bitwise: & | ^ ~
  • logical: && || !
  • comparisons: < <= > >= == !=
  • assignment: =
• Statements:
  • blocks
  • expression statements
  • if / else
  • while
  • for
  • break
  • continue
  • return
• Functions:
  • function definitions and calls
  • integer return types
  • main entry required

Builtin Runtime Functions

• printf(int) is available as a builtin import.
• Current implementation is intentionally minimal: it prints one integer per call.
• Full libc printf formatting is not implemented in this tiny subset.

Out of Scope

• pointers
• arrays
• structs
• floating-point types
• preprocessor/macros
• full libc integration

Build

cargo build

Build WebAssembly For Browser Use

wasm-pack build --target web --out-dir web-next/public/wasm --out-name emberc_wasm

This exports a browser-loadable module with compileToWat.

Run

cargo run -- examples/add.c -o examples/add.wat

If -o is omitted, emberc writes output next to input with a .wat extension.

Test

cargo test

Next.js Demo

A small editor + compile UI is provided in web-next/README.md.

Quick start:

wasm-pack build --target web --out-dir web-next/public/wasm --out-name emberc_wasm
cd web-next
npm install
npm run dev