* Remove Dhall.X and replace with Data.Void
This commit removes the Dhall.X module and the Dhall.X.X type,
preferring the use of Data.Void.Void. As I'm sure a lot of people are
actually using X, I've added a type-alias type X = Void. However,
pattern matching on X would be a breaking change.
Fixes#1120.
* Restore unsafeCoerce
* Fix regression
* Unused
* Reorganise exports
* Fix dhall-nix
* Another fix
* Fix Dhall.LSP.Backend.Typing
* Fix dhall-bash
These aren't fully static executables (they still have some
`/nix/store` references), but they at least compile Haskell dependencies
statically. That means that they can be `nix-env --install`ed side-by-side
with other Haskell executables, which would otherwise conflict with an
error like this one:
```
error: packages '/nix/store/hrxnlwlsiw5jjjkq5v6ihcwb0shx4fga-dhall-1.20.1/lib/li
nks/libHSbasement-0.0.8-8QjArDsw3GWCcbHE5iqtz3-ghc8.4.3.dylib' and '/nix/store/d
2y5373anwf1q3h86ar3lljk11k1lq0h-dhall-json-1.2.6/lib/links/libHSbasement-0.0.8-8
QjArDsw3GWCcbHE5iqtz3-ghc8.4.3.dylib' have the same priority 5; use 'nix-env --s
et-flag priority NUMBER INSTALLED_PKGNAME' to change the priority of one of the
conflicting packages (0 being the highest priority)
```
This adds four new sections to the page after the live demo which highlight
the common themes that I notice people use when communicating the value of
Dhall to others on social media:
* The first section emphasizes the element of delight in using the language for
people who are into elegance and quality
* The second section focuses on more pragmatic people who are sick of YAML and
just want a reasonable alternative that they can convince their manager to
adopt
* The third section appeals to the LangSec crowd that wants an uncompromising
and secure foundation for what they are buliding
* The last section targeted at the skeptic who thinks that Dhall is an ivory
tower language not suited for real-world problems.
The second crowd (YAML emigrants) is the audience that I'm targeting the
most strongly at the moment, but I didn't want to lead with a negative reason
adopt by focusing on the limitations of YAML, so I put the section on delight
first so that we could start with a more positive tone.
This expands the "Try dhall" page to serve as a functional home page for
"dhall-lang.org" in the short term by making the following changes:
* Adding a navigation bar to the top that links to useful resources and
official integrations
* Adding a quick summary explaining what Dhall is
This updates all of the `README`s to:
* centralize all of the build/install/develop information in the
top-level `README`
* get the nested `README`s to use a consistent style
This ensures that all of the `dhall-*` libraries build against
GHC 8.6.1, but still generates tarballs using GHC 8.4.3 and
uses GHC 8.4.3 for development
The motivation for this change is:
* To catch build failures in downstream packages whenever we make a breaking
change to the `dhall` API
* To reduce the amount of work I need in order to cut a release for all of
these packages
* To better share Nix/CI-related logic between the projects
Note that I have not yet migrated `dhall-nix` in. I'm waiting for
https://github.com/dhall-lang/dhall-nix/issues/17 to be fixed since
`dhall-nix` is incompatible with later versions of `megaparsec` due to
`hnix`.
