From d7ad3d09f7afc7296aede051ca0919b720bcb988 Mon Sep 17 00:00:00 2001 From: Nexoniarz Date: Sun, 25 Oct 2026 19:49:21 +0100 Subject: [PATCH] docs: Finch builds itself; what is left before main switches Co-Authored-By: Claude Sonnet 5.5 Claude-Session: https://claude.ai/code/session_015f73FesGZGYPkmDvUcj6QX --- docs/plan/finch.md | 48 +++++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 26 deletions(-) diff --git a/docs/plan/finch.md b/docs/plan/finch.md index c73b240..0411a4c 100644 --- a/docs/plan/finch.md +++ b/docs/plan/finch.md @@ -57,36 +57,32 @@ Measured from the repository, not from its README alone: the headers in `include/uapi/`, so they are not hand-written and cannot drift from the kernel. -## The self-hosting gap +## Where self-hosting stands -"Rewrite it in Finch itself" was mostly done before this was written: `boot/` -compiled itself. What it lacked is stated by its own test, `tests/boot.sh`, -which skips every test using a feature `boot/` does not have. Measured against -that test, on the branch `finish-finch` of the Finch repository (kept in the -author's checkout, `Projects/Finch`, as a branch on top of `embed`): +The Finch compiler written in Finch (`boot/`) now **builds itself**: stage 2 and +stage 3 are byte-identical (58,660 lines of LLVM IR), and it passes all 22 of +the repository's run tests (the C++ one passes 77/77). The work is on the +`finish-finch` branch of `github.com/Nexoniarz/Finch`; `before-bootstrap` there +is the all-C++ compiler, kept as the backup. `main` is untouched. -| Feature | `boot/` | Notes | -|---|---|---| -| sized numbers (`i8`..`u64`, `f32`), conversions | **done** | `int` and `float` stay the i64 and f64 defaults | -| methods (`fn T.m`), mutation analysis | **done** | | -| `defer` | **done** | | -| errors as values (`-> T!`, `error`, `try`, `or`) | **done** | including `fn main() -> !` | -| maps, `for k, v in`, `for i, x in` | **done** | | -| `str(x)` of any value | **done** | | -| **C import** (`import "x.h"`, `link`, C structs by value) | **missing** | the one that matters for SchOS: libclang through Finch's own C import, then the System V struct ABI | -| target and ABI layer (AArch64, macOS, Windows) | missing | after C import | -| language server | missing | `lsp.cpp`, 580 lines | +What the self-hosted compiler has: sized numbers, methods, `defer`, errors as +values, maps, `for k, v in`, C import through libclang (written in Finch, in +`boot/cimport.fch`), C structs by value and `addr(fn)` callbacks (System V +x86-64), `run`, `build`, `ir`, `version`, `-O0`, `-l`, `-I`. -The self-hosted compiler passes 17 of 22 tests and compiles itself to -byte-identical output; the five it skips all import C. **C import is the next -piece, and the last one before the C++ compiler is only a seed.** It is a few -thousand lines of Finch (`cimport.cpp` and `abi.cpp` are 740 in C++), done in two -steps so each can be tested: functions, constants, globals and pointers first -(`cimport`, `c_pointers`), struct layout and the calling convention second -(`c_structs`). +What it does **not** have yet, and the C++ compiler does: -The scratch files `note.txt` and `notatka.txt` in the repository are not -Finch's and can go. +| | | +|---|---| +| `-g` debug info | text IR needs the DWARF metadata written by hand | +| `--target` (Windows, ARM64, macOS) | their struct-passing rules (`abi.cpp`) and linkers | +| `lsp`, the editor language server | `lsp.cpp`, 580 lines | +| `export fn`, `build --shared` | on the author's local `embed` branch | + +**`main` becomes the Finch-written compiler when those are in**, so that +nothing a user does today stops working; until then it is the seed that builds +the first stage. The new language features (enums, `match`, generics, a +standard library) come before that switch, as simple as the rest of the language. ## Rules