ok
fb1395c740
- DOES> with split-compilation for defining words (CREATE , DOES> @ pattern) - EVALUATE for string interpretation - Double-cell: M* UM* UM/MOD FM/MOD SM/REM S>D */ */MOD - Parsing: WORD FIND COUNT >NUMBER >IN STATE - Memory: CMOVE CMOVE> - Compile-time: ABORT" S" (compile mode) - 219 tests passing, ~90% Core word set coverage - Update docs to reflect current implementation
58 lines
2.6 KiB
Markdown
58 lines
2.6 KiB
Markdown
# WAFER Project Conventions
|
|
|
|
## What is WAFER?
|
|
WAFER (WebAssembly Forth Engine in Rust) is an optimizing Forth 2012 compiler targeting WebAssembly. Currently a working Forth system with 70+ words and JIT compilation.
|
|
|
|
## Architecture
|
|
- Each Forth word compiles to its own WASM module via `wasm-encoder`
|
|
- Modules share memory, globals (dsp/rsp), and a function table via wasmtime imports
|
|
- IR-based compilation: Forth -> `Vec<IrOp>` -> WASM codegen -> wasmtime instantiation
|
|
- Dictionary: linked-list in a `Vec<u8>` buffer simulating WASM linear memory
|
|
- Primitives: either IR-based (compiled to WASM) or host functions (Rust closures in wasmtime)
|
|
|
|
## Key Files
|
|
- `crates/core/src/outer.rs` -- ForthVM: the main runtime, outer interpreter, compiler, all primitives
|
|
- `crates/core/src/codegen.rs` -- IR-to-WASM translation, module generation, wasmtime execution tests
|
|
- `crates/core/src/dictionary.rs` -- Dictionary data structure with create/find/reveal
|
|
- `crates/core/src/ir.rs` -- IrOp enum (the intermediate representation)
|
|
- `crates/core/src/memory.rs` -- Memory layout constants (stack regions, dictionary base, etc.)
|
|
- `crates/cli/src/main.rs` -- CLI REPL with rustyline
|
|
|
|
## Adding a New Word
|
|
|
|
**IR primitive** (simple stack/arithmetic/logic -- preferred when possible):
|
|
```rust
|
|
self.register_primitive("WORD_NAME", false, vec![IrOp::Dup, IrOp::Mul])?;
|
|
```
|
|
|
|
**Host function** (needs Rust logic -- I/O, dictionary manipulation, complex stack access):
|
|
```rust
|
|
let func = Func::new(&mut self.store, func_type.clone(), move |mut caller, _params, _results| {
|
|
// manipulate memory/globals directly
|
|
Ok(())
|
|
});
|
|
self.register_host_primitive("WORD_NAME", false, func)?;
|
|
```
|
|
|
|
**Special interpreter token** (defining words like VARIABLE, CONSTANT, CREATE):
|
|
Handle in `interpret_token_immediate()` or `compile_token()` as a special case.
|
|
|
|
## Code Style
|
|
- `cargo fmt --all` and `cargo clippy --workspace` must pass with no warnings
|
|
- Every public function needs a doc comment
|
|
- Use `thiserror` for error types in core crate, `anyhow` for CLI
|
|
- Prefer returning `Result` over panicking
|
|
|
|
## Testing
|
|
- Run `cargo test --workspace` before committing (currently 185 tests)
|
|
- Forth 2012 compliance: `cargo test -p wafer-core --test compliance`
|
|
- Test helper in outer.rs: `eval_output("forth code")` returns printed output as String
|
|
- Test helper: `eval_stack("forth code")` returns data stack as Vec<i32>
|
|
|
|
## Key Principles
|
|
1. Correctness first, performance second
|
|
2. Maximize Forth, minimize Rust (self-hosting goal -- not yet started)
|
|
3. Test-driven: if it's not tested, it doesn't work
|
|
4. Every word set at 100% compliance before moving to the next
|
|
5. Never break existing tests
|