ee24f93a8b | ||
---|---|---|
.github/workflows | ||
benchmarks | ||
data | ||
doc | ||
main | ||
src | ||
tests | ||
.gitignore | ||
.gitmodules | ||
CHANGELOG.md | ||
CODEOWNERS | ||
LICENSE | ||
Makefile | ||
README-design.md | ||
README.md | ||
Setup.hs | ||
brittany.yaml | ||
build.sh | ||
cabal.project | ||
default.nix | ||
hnix.cabal | ||
hydra.json | ||
jobsets.nix | ||
release.nix | ||
shell.nix |
README.md
hnix
Parser, evaluator and type checker for the Nix language written in Haskell.
Contents
- Prerequisites
- Getting Started
- Development status loop with amazing
ghcid
- Using the HNix REPL
- Nix laziness
- Contributing
- Evaluating Nixpkgs with HNix
Prerequisites
Tooling is WIP, nix-shell
and nix-store
are still used for their purpose, so, to access them Nix is required to be installed.
Getting Started
# Note: --recursive
git clone --recursive https://github.com/haskell-nix/hnix.git
cd hnix
Cachix prebuild binary caches
If you opt in to use of Nix environment, please enable the official HNix Cachix binary cache:
-
Go through https://cachix.org/ and set it up.
-
Run:
cachix use hnix
Development using Cabal
Cabal Quickstart.
- (Optional), to enter the projects reproducible Nix environment:
nix-shell
- Building:
cabal v2-configure
cabal v2-build
- Loading the project into
ghci
REPL:
cabal v2-repl
- Testing:
- Default suite:
cabal v2-test
- All available tests:
env ALL_TESTS=yes cabal v2-test
- Selected (list of tests is in
tests/Main.hs
):
env NIXPKGS_TESTS=yes PRETTY_TESTS=1 cabal v2-test
Building the project
With benchmarks
To run benchmarks:
cabal v2-bench
With profiling
To build hnix
with profiling enabled:
cabal v2-configure --enable-tests --enable-profiling --flags=profiling
cabal v2-run hnix -- <args> +RTS -p
With full debug info
To build hnix
for debugging, with full tracing output and stack traces:
cabal v2-configure --enable-tests --enable-profiling --flags=profiling --flags=tracing
cabal v2-run hnix -- -v5 --trace <args> +RTS -xc
Note that this going to run quite slowly, but would give the most information as to what happens during parsing & evaluation.
Run HNix
cabal v2-run hnix -- --help
(--
is for separation between cabal
& hnix
args)
Use of the Nix-build
There is a number of build options to use with nix-build
, documentation of them is in: ./default.nix
, keys essentially pass-through the Nixpkgs Haskell Lib API.
Options can be used as:
nix-build \
--arg <option1> <argument1> \
--arg <option2> <argument2> \
--argstr <option3> "<strinTypeArg>"
Run benchmarks
nix-build \
--arg disableOptimization false \
--arg enableDeadCodeElimination true \
--arg doStrip true \
--arg doBenchmark true
With profiling
nix-build \
--arg disableOptimization false \
--arg enableDeadCodeElimination true \
--arg enableLibraryProfiling true \
--arg enableExecutableProfiling true
With full debug info
nix-build \
--arg disableOptimization false \
--arg enableDeadCodeElimination true \
--arg doBenchmark true \
--arg doStrip false \
--arg enableLibraryProfiling true \
--arg enableExecutableProfiling true
--arg doTracing true \
--arg enableDWARFDebugging true
Run the result
./result/bin/hnix
Development status loop with amazing ghcid
ghcid --command="cabal v2-repl --repl-options=-fno-code --repl-options=-fno-break-on-exception --repl-options=-fno-break-on-error --repl-options=-v1 --repl-options=-ferror-spans --repl-options=-j"
(optional) To use projects reproducible environment, wrap ghcid ...
command into a nix-shell --command ' '
.
For simplicity alias
the command in your shell.
Using the HNix REPL
Enter in:
hnix --repl
Evaluate an expression:
hnix --eval -E '(import <nixpkgs> {}).pkgs.hello' --repl
This also binds the evaluated expression result to the input
variable, so that variable can be inspected.
Use the :help
command for a list of all available REPL commands.
Nix laziness
Nix is a lazy language with the ability of recursion, so by default REPL and eval prints are lazy:
hnix \
--eval \
--expr '{ x = true; }'
{ x = "<CYCLE>"; }
To disable laziness add the --strict
to commands or :set strict
in the REPL.
hnix \
--eval \
# Strictly \
--strict \
--expr '{ x = true; }'
{ x = true; }
Contributing
-
If something in the quests looks interesting, look through the thread and leave a comment taking it, to let others know you're working on it.
-
You are free to chat with everyone on Gitter.
-
When the pull request is ready to be submitted, to save time - please, test it with:
git submodule update --init --recursive
nix-shell --run "LANGUAGE_TESTS=yes cabal v2-test"
Please, check that all tests that were passing prior (most probably all tests mentioned in the command) are still passing for the PR, it is faster to check that locally than through CI. It's OK if no new tests are passing.
Evaluating Nixpkgs with HNix
Currently, the main high-level goal is to be able to evaluate all of Nixpkgs:
hnix --eval -E "import <nixpkgs> {}" --find