* Initial draft of the json-to-dhall tool
* Homogenous JSON maps -> Dhall association lists. Bower example.
* Default conversion options. Ghci examples in function annotations.
* Added type signature to text color highlighting functions (error
reporing)
* Removed TypeApplications extension
* Explicit semigroups
* Disable ghc < 8.0 build
* Type specifications for 'None's (e.g. None Integer instead of just None)
* New style for unions, e.g.: < Left : Text | Right : Integer >.Right +1
... as standardized in https://github.com/dhall-lang/dhall-lang/pull/438
This also adds `dhall-json` support for empty alternatives
In particular, this translates empty alternatives to strings encoding the alternative name
```haskell
-- ./example.dhall
let Role = < Wizard | Fighter | Rogue >
in [ Role.Wizard, Role.Fighter ]
```
```
$ dhall-to-json <<< './example.dhall'
["Wizard","Fighter"]
```
... as proposed in https://github.com/dhall-lang/dhall-kubernetes/issues/46#issuecomment-468530601
`--omitEmpty` is the same as `--omitNull` except it also omits fields that
are empty records. To be precise, it omits fields whose transitive fields
are all `null` (and an empty record is a special case of a record whose
transitive fields are all `null` since it is vacuously true when there are
no fields).
This allows Dhall configurations that target YAML to avoid having to nest
sub-records inside of an `Optional` value. Omitting unnecessary `Optional`
layers reduces the number of default values that the configuration format
needs to thread around.
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
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`.
