hhc

hhc is the GCC-based compiler for H#, the programming language of HackerOS.

It is built the same way the D language gets gdc: H# is a frontend inside the GNU Compiler Collection. GCC's own backend does the optimisation and code generation, so hhc produces native code for every architecture GCC supports.

H# source  ->  hsharp1 (lexer, parser, checker -> GENERIC)  ->  GCC middle/back end  ->  binary
                 ^ this repository                              ^ stock GCC

binary	what it is	GCC counterpart
hhc	compiler driver (the command you run)	gcc / gdc
hsharp1	the compiler proper (installed in libexec)	cc1 / d21

The existing h# tool (Rust + LLVM, interpreter, package tooling) lives in the H-Sharp repository; hhc is the GCC route to the same language.

Using it

hhc hello.h# -o hello && ./hello
hhc -O2 prog.h# -o prog
hhc -S prog.h#                 # assembly
hhc -fsyntax-only prog.h#      # check only

;; hello.h#
fn main() is
    write("Hello from H#!")
end

Building hhc from source

Everything is driven by a small pure-Lua 5.5 build system (no Lua libraries needed). It fetches the newest stable GCC release straight from git, drops the H# frontend into the tree, configures, builds, installs, tests and packages.

sh scripts/bootstrap-lua.sh           # only if you do not have lua5.5 yet
lua5.5 hhc.lua deps                 # apt / dnf / pacman / zypper packages
lua5.5 hhc.lua all                  # fetch -> overlay -> configure -> build -> install -> test -> package
./_install/bin/hhc --version

Single steps, useful while hacking on the frontend:

lua5.5 hhc.lua overlay              # re-sync frontend/gcc/hsharp into the GCC tree
lua5.5 hhc.lua build                # incremental: only the changed frontend files rebuild
lua5.5 hhc.lua install
lua5.5 hhc.lua test

Useful options: --ref=master (GCC trunk), --ref=releases/gcc-15.2.0, --prefix=/opt/hhc, --jobs=8, --with-cxx, --bootstrap, --ccache. lua5.5 hhc.lua help lists everything.

A full build needs roughly 1-2 hours on 4 cores and ~10 GB of disk.

CI

.github/workflows/build.yml does the same on GitHub Actions for x86_64 and aarch64: it resolves the newest stable GCC, builds it with the frontend, runs tests/cases, uploads the tarballs and (on v* tags) publishes a release. A weekly schedule picks up new GCC releases on its own.

Repository layout

hhc.lua                      build driver entry point (Lua 5.5)
build/
  config.lua                 defaults (GCC ref, languages, prefix, ...)
  lib/                       log, sh, args, gccver, state
  steps/                     doctor deps fetch overlay configure compile
                             install test package clean
frontend/
  gcc/hsharp/                the GCC frontend  ->  copied to <gcc>/gcc/hsharp
  patches/                   optional patches for core GCC files, per release
scripts/bootstrap-lua.sh     get lua5.5 (apt, lua.org, or GitHub mirror)
tests/
  cases/                     *.h# programs + .expected / .expected_error
  selftest.lua               unit tests of the build scripts
docs/                        architecture and language-subset notes
.github/workflows/build.yml  CI

Status: what the frontend supports today

hhc is at stage 0: a real, working GCC frontend covering a core subset of H#, designed to grow. Supported: functions (incl. fn f() = expr, recursion), let / let mut, all integer types, f32/f64, bool, string literals, arithmetic / comparison / logical operators, if-elsif-else, while, loop, for i in a..b / a..=b, break, continue, return, write(), to_string(), {name} interpolation inside write strings.

Not yet: structs, enums, traits, generics, closures, modules/use, arrays, match, FFI, async, runtime string concatenation outside write. See docs/LANGUAGE-SUBSET.md and the roadmap in docs/ARCHITECTURE.md.

License

BSD 3-Clause, see LICENSE. The frontend is built against and linked into GCC, which is GPLv3+; binary distributions of hhc therefore follow GCC's licensing.