ok2
13a16ae2a4
- README: add performance section (beats gforth 2-10x), update test commands, note self-recursive direct calls and loop promotion - CLAUDE.md: update test counts (427 unit + comparison tests) - OPTIMIZATIONS.md: stack-to-local Phase 1→Phase 2 (loops + IF), DO/LOOP locals done, J as IR done, add section 14 (self-recursive direct call), add current performance table vs gforth - WAFER.md: document self-recursive call optimization, CONSOLIDATE, update test commands and line counts - FORTH.md: expanded space history, add FORTH-IN-SPACE.md reference - FORTH-IN-SPACE.md: new document with verified spacecraft history
71 lines
3.4 KiB
Markdown
71 lines
3.4 KiB
Markdown
# WAFER Project Conventions
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## What is WAFER?
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WAFER (WebAssembly Forth Engine in Rust) is an optimizing Forth 2012 compiler targeting WebAssembly. Currently a working Forth system with 200+ words, JIT compilation, 12 word sets at 100% compliance, and a full optimization pipeline (peephole, constant folding, inlining, strength reduction, DCE, tail calls, stack-to-local promotion with loop/IF support, self-recursive direct calls, consolidation). Beats gforth on all benchmarks in release mode.
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## Architecture
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- Each Forth word compiles to its own WASM module via `wasm-encoder`
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- Modules share memory, globals (dsp/rsp), and a function table via wasmtime imports
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- IR-based compilation: Forth -> `Vec<IrOp>` -> WASM codegen -> wasmtime instantiation
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- Dictionary: linked-list in a `Vec<u8>` buffer simulating WASM linear memory
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- Primitives: either IR-based (compiled to WASM) or host functions (Rust closures in wasmtime)
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## Key Files
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- `crates/core/src/outer.rs` -- ForthVM: the main runtime, outer interpreter, compiler, all primitives
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- `crates/core/src/codegen.rs` -- IR-to-WASM translation, module generation, wasmtime execution tests
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- `crates/core/src/dictionary.rs` -- Dictionary data structure with create/find/reveal
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- `crates/core/src/ir.rs` -- IrOp enum (the intermediate representation)
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- `crates/core/src/memory.rs` -- Memory layout constants (stack regions, dictionary base, etc.)
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- `crates/core/src/optimizer.rs` -- IR optimization passes (peephole, fold, inline, DCE, etc.)
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- `crates/core/src/config.rs` -- WaferConfig: unified optimization configuration
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- `crates/core/src/consolidate.rs` -- Consolidation recompiler (single-module direct calls)
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- `crates/cli/src/main.rs` -- CLI REPL with rustyline
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## Adding a New Word
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**IR primitive** (simple stack/arithmetic/logic -- preferred when possible):
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```rust
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self.register_primitive("WORD_NAME", false, vec![IrOp::Dup, IrOp::Mul])?;
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```
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**Host function** (needs Rust logic -- I/O, dictionary manipulation, complex stack access):
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```rust
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let func = Func::new(&mut self.store, func_type.clone(), move |mut caller, _params, _results| {
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// manipulate memory/globals directly
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Ok(())
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});
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self.register_host_primitive("WORD_NAME", false, func)?;
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```
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**Special interpreter token** (defining words like VARIABLE, CONSTANT, CREATE):
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Handle in `interpret_token_immediate()` or `compile_token()` as a special case.
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## Code Style
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- `cargo fmt --all` and `cargo clippy --workspace` must pass with no warnings
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- Every public function needs a doc comment
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- Use `thiserror` for error types in core crate, `anyhow` for CLI
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- Prefer returning `Result` over panicking
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## Testing
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- Run `cargo test --workspace` before committing (currently 427 unit + 1 benchmark + 11 compliance + 11 comparison)
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- Forth 2012 compliance: `cargo test -p wafer-core --test compliance`
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- Cross-engine comparison (vs gforth): `cargo test -p wafer-core --test comparison`
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- Performance benchmarks (release mode): `cargo test -p wafer-core --test comparison -- --nocapture --ignored`
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- Test helper in outer.rs: `eval_output("forth code")` returns printed output as String
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- Test helper: `eval_stack("forth code")` returns data stack as Vec<i32>
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## Key Principles
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1. Correctness first, performance second
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2. Maximize Forth, minimize Rust (self-hosting goal -- not yet started)
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3. Test-driven: if it's not tested, it doesn't work
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4. Every word set at 100% compliance before moving to the next
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5. Never break existing tests
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