Platforms & Ports
The core compiler and VM described in Architecture target desktop Linux, but the same bytecode format is designed to run identically everywhere. Lumen currently spans four targets:
| Target | What runs | Notes |
|---|---|---|
| Desktop (Linux/Arch) | Full toolchain — compiler, VM, debugger, disassembler | The lumen CLI described throughout this book |
| Raspberry Pi Pico | VM only, bare-metal C | No compiler on-device — bytecode is cross-compiled on desktop and flashed/loaded onto the Pico |
| AVR | VM only, bare-metal C | Same split as Pico: desktop compiles, AVR executes |
| WebAssembly | Full toolchain, in-browser | Powers the Lumen Playground; can also export compiled programs as QR codes |
| Android | Full toolchain — editor, compiler, VM, disassembler, JNI-wrapped | Also has a QR scanner for importing programs compiled elsewhere; not the only way to get a program onto the device |
Why Pico and AVR ship the VM without the compiler
Pico and AVR ship the VM (execute() and its surrounding loop, see The Virtual Machine) but not the compiler. This is a deliberate split, specific to those two microcontroller targets:
- The compiler depends on the C++ standard library’s string handling and file I/O in ways that either don’t exist or aren’t worth porting to a microcontroller.
- Compiled bytecode (a
.binfile, see Bytecode Format) is a small, flat, self-describing blob — trivial to embed as a C byte array or flash over a wire. - Keeping compilation on desktop means the Pico and AVR VMs only have to get
execute()right, not an entire tokenizer/parser/codegen pipeline.
So the workflow on Pico and AVR is the same shape: compile on desktop, transfer the .bin, run the VM on-device, as a flashed C byte array in both cases.
Android and WebAssembly don’t follow this split — both ship the full compiler alongside the VM, so a program can be written and compiled without ever leaving the device or browser. Android’s QR scanner is a convenience for importing bytecode compiled elsewhere, not a substitute for an on-device compiler it lacks.
Native function tables per target
Built-in Functions covers this in more detail, but the short version: desktop dispatches EXEC through funcMap, a table of C++ lambdas. Embedded targets (Pico, AVR) use funcTable, a plain array of NativeFn function pointers, with indices 0xD0–0xFF reserved for host-specific natives like GPIO calls. This split lets each platform expose exactly the native functions that make sense for it — printing and input on desktop, pin control on a microcontroller — without changing the VM’s core dispatch loop.