Merge request #724 README-clean-up

Casual readme clean-up.

Related to #726

Mainly making the language more to the point, terse, direct, and so - understandable.
Also structuring of the text.
Some fixes to the shell sections. Some of them are still out of dare, would go into fixing all commands in the upcoming PRs.

Parsed results: https://github.com/Anton-Latukha/hnix/tree/2020-09-28-README-clean-up
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@ -10,39 +10,62 @@
Haskell parser, evaluator and type checker for the Nix language. Haskell parser, evaluator and type checker for the Nix language.
## Prerequisites ## Contents
Nix is installed and in your `$PATH`. This is so that `nix-store` can be used <!-- TOC -->
for interacting with store paths, until `hnix-store` is ready. - [Prerequisites](#prerequisites)
- [Getting Started](#getting-started)
- [Using the REPL](#using-the-repl)
- [Building with full debug info](#building-with-full-debug-info)
- [Building with benchmarks enabled](#building-with-benchmarks-enabled)
- [Building with profiling enabled](#building-with-profiling-enabled)
- [Using the Cachix binary cache](#using-the-cachix-binary-cache)
- [Contributing](#contributing)
- [Evaluating Nixpkgs with HNix](#evaluating-nixpkgs-with-hnix)
<!-- /TOC -->
## Prerequisites
Until `hnix-store` is ready, `nix-store` is still used for interacting with the store paths, so Nix is still required installed and available through `$PATH`.
## Getting Started ## Getting Started
``` ```
$ git clone --recursive https://github.com/haskell-nix/hnix.git git clone --recursive https://github.com/haskell-nix/hnix.git
... cd hnix
$ cd hnix nix-shell
$ nix-shell cabal v2-configure --enable-tests
$ cabal v2-configure --enable-tests cabal v2-build
$ cabal v2-build ```
$ cabal v2-test
# To run all of the tests, which takes up to a minute: Run testing:
$ env ALL_TESTS=yes cabal v2-test * Default:
# To run only specific tests (see `tests/Main.hs` for a list) ```
$ env NIXPKGS_TESTS=yes PRETTY_TESTS=1 cabal v2-test cabal v2-test
$ ./dist/build/hnix/hnix --help ```
* All:
```
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
```
Run built binary with Cabal (`--` is for separation between `cabal` & `hnix` args):
```
cabal v2-run hnix -- --help
``` ```
## Using the REPL ## Using the REPL
To enter the `hnix` REPL use Enter REPL:
``` ```
hnix --repl hnix --repl
``` ```
To evaluate an expression and make it available in the REPL To evaluate an expression and make it available in the REPL as the `input` variable use:
as the `input` variable use
``` ```
hnix --eval -E '(import <nixpkgs> {}).pkgs.hello' --repl hnix --eval -E '(import <nixpkgs> {}).pkgs.hello' --repl
``` ```
@ -51,28 +74,26 @@ Use the `:help` command for a list of all available REPL commands.
## Building with full debug info ## Building with full debug info
To build `hnix` for debugging, and with full tracing output and stack traces, To build `hnix` for debugging, and with full tracing output and stack traces, use:
use:
``` ```
$ nix-shell nix-shell
$ cabal v2-configure --enable-tests --enable-profiling --flags=profiling --flags=tracing cabal v2-configure --enable-tests --enable-profiling --flags=profiling --flags=tracing
$ cabal v2-build cabal v2-build
$ ./dist/build/hnix/hnix -v5 --trace <args> +RTS -xc cabal v2-run hnix -- -v5 --trace <args> +RTS -xc
``` ```
Note that this will run quite slowly, but will give the most information as to Note that this will run quite slowly, but will give the most information as to what might potentially be going wrong during parsing or evaluation.
what might potentially be going wrong during parsing or evaluation.
## Building with benchmarks enabled ## Building with benchmarks enabled
To build `hnix` with benchmarks enabled: To build `hnix` with benchmarks enabled:
``` ```
$ nix-shell --arg doBenchmarks true nix-shell
$ cabal v2-configure --enable-tests --enable-benchmarks cabal v2-configure --enable-tests --enable-benchmarks
$ cabal v2-build cabal v2-build
$ cabal v2-bench cabal v2-bench
``` ```
## Building with profiling enabled ## Building with profiling enabled
@ -80,60 +101,40 @@ $ cabal v2-bench
To build `hnix` with profiling enabled: To build `hnix` with profiling enabled:
``` ```
$ nix-shell nix-shell
$ cabal v2-configure --enable-tests --enable-profiling --flags=profiling cabal v2-configure --enable-tests --enable-profiling --flags=profiling
$ cabal v2-build cabal v2-build
$ ./dist/build/hnix/hnix <args> +RTS -p cabal v2-run hnix -- <args> +RTS -p
``` ```
## Building with GHCJS
From the project root directory, run:
```
$ NIX_CONF_DIR=$PWD/ghcjs nix-build ghcjs
```
This will build an `hnix` library that can be linked to your GHCJS
application.
## Using the Cachix binary cache ## Using the Cachix binary cache
If you're on macOS, you can use the binary cache at Cachix to avoid building If you're on macOS, you can use the binary cache at Cachix to avoid building the specific dependencies used by hnix. Just use these commands:
the specific dependencies used by hnix. Just use these commands:
``` ```
$ nix-env -iA cachix -f https://github.com/NixOS/nixpkgs/tarball/db557aab7b690f5e0e3348459f2e4dc8fd0d9298 nix-env -iA cachix -f https://github.com/NixOS/nixpkgs/tarball/db557aab7b690f5e0e3348459f2e4dc8fd0d9298
$ cachix use hnix cachix use hnix
``` ```
## How you can help ## Contributing
### Issue Tracker Backlog 1. If something in the [quests](https://github.com/haskell-nix/hnix/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22+no%3Aassignee) looks interesting, look through the thread and leave a comment taking it, to let others know you're working on it.
If you're looking for a way to help out, try taking a look 2. You are free to chat with everyone on [Gitter](https://gitter.im/haskell-nix/Lobby).
[here](https://github.com/haskell-nix/hnix/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22+no%3Aassignee).
When you find an issue that looks interesting to you, comment on the ticket to
let others know you're working on it; look for others who might have done the
same. You can talk with everyone live on
[Gitter](https://gitter.im/haskell-nix/Lobby).
When you're ready to submit a pull request, test it with: 3. When pull request is ready to be submitted, to save time - please, test it with:
``` ```
$ git submodule update --init --recursive git submodule update --init --recursive
$ nix-shell --run "LANGUAGE_TESTS=yes cabal v2-test" nix-shell --run "LANGUAGE_TESTS=yes cabal v2-test"
``` ```
Make sure that all the tests that were passing prior to your PR are still 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 chech that locally then through CI. It's OK if no new tests are passing.
passing afterwards; it's OK if no new tests are passing.
### Evaluating Nixpkgs with HNix ### Evaluating Nixpkgs with HNix
Currently the main high-level goal is to be able to evaluate all of nixpkgs. To Currently the main high-level goal is to be able to evaluate all of Nixpkgs. To run this yourself, first build `hnix` with `nix-build`, then run the following command:
run this yourself, first build hnix with `nix-build`, then run the following
command:
``` ```
$ ./result/bin/hnix --eval -E "import <nixpkgs> {}" --find ./result/bin/hnix --eval -E "import <nixpkgs> {}" --find
``` ```