This PR adds a version number to the module name of the
`PackageDescription` module. This allows us to change the Package file
format in a backwards compatible way in the future.
Now the simplest Package.juvix file looks like:
```
module Package;
import PackageDescription.V1 open;
package : Package := defaultPackage;
```
## Adding new versions
The idea is that new versions of the PackageDescription format will be
added as files of the form:
include/package/PackageDescription/Vx.juvix
The correspondence between a version of the PackageDescription file and
the package type name is recorded in
[`packageDescriptionTypes`](9ba869d836/src/Juvix/Compiler/Pipeline/Package/Loader.hs (L15)).
The `package` identifier type must come from **one** of the versions
of the PackageDescription module.
* Closes https://github.com/anoma/juvix/issues/2452
Depends on:
* ~~https://github.com/anoma/juvix/pull/2459~~
* https://github.com/anoma/juvix/pull/2462
This PR is part of a series implementing:
* https://github.com/anoma/juvix/issues/2336
This PR adds the package file loading function, including a file
evaluation effect. It integrates this with the existing `readPackage`
function and adds tests / smoke tests.
## Package.juvix format
Instead of `juvix.yaml` (which is still supported currently) users can
now place a `Package.juvix` file in the root of their project. The
simplest `Package.juvix` file you can write is:
```
module Package;
import PackageDescription open;
package : Package := defaultPackage;
```
The
[PackageDescription](35b2f618f0/include/package/PackageDescription.juvix)
module defines the `Package` type. Users can use "go-to definition" in
their IDE from the Package file to see the documentation and
definitions.
Users may also import `Stdlib.Prelude` in their Package file. This is
loaded from the global project. No other module imports are supported.
Notes:
* If a directory contains both `Package.juvix` and `juvix.yaml` then
`Package.juvix` is used in preference.
## Default stdlib dependency
The `Dependency` type has a constructor called `defaultStdlib`. This
means that any project can use the compiler builtin standard library
dependency. With `juvix.yaml` this dependency is only available when the
`dependencies` field is unspecified.
```
module Package;
import PackageDescription open;
package : Package := defaultPackage { dependencies := [defaultStdlib] };
```
## Validation
As well as the standard type checking validation that the Juvix compiler
provides additional validation is made on the file.
* The Package module must contain the identifier `package` and it must
have type `Package` that's obtained from the global `PackageDescription`
module.
* Every dependency specified in the Package.juvix must be unique.
* Closes https://github.com/anoma/juvix/issues/2336
## Examples
### Package with name and version
```
module Package;
import PackageDescription open;
package : Package :=
defaultPackage {name := "a-package";
version := mkVersion 0 1 0};
```
### Package with GitHub dependency
```
module Package;
import PackageDescription open;
package : Package :=
defaultPackage {name := "a-package";
version := mkVersion 0 1 0;
dependencies := [defaultStdlib;
github (org := "anoma";
repo := "juvix-containers";
ref := "v0.7.1")]};
```
## Package with main and buildDir fields
```
module Package;
import Stdlib.Prelude open;
import PackageDescription open;
package : Package :=
defaultPackage {name := "a-package";
version := mkVersion 0 1 0;
dependencies := [defaultStdlib;
github (org := "anoma";
repo := "juvix-containers";
ref := "v0.7.1")];
buildDir := just "/tmp/build";
main := just "HelloWorld.juvix"
};
```
The special PathResolver puts files from the global package stdlib and
files from the global package description files in scope of the
$root/Package.juvix module.
Currently this means that PackageDescription module is in scope for the
module so that the user can write:
```
module Package;
import Stdlib.Prelude open;
import PackageDescription open;
package : Package :=
mkPackageDefault
(name := "foo")
{ version := mkVersion 0 1 0
; dependencies :=
[ github "anoma" "juvix-stdlib" "adf58a7180b361a022fb53c22ad9e5274ebf6f66"
; github "anoma" "juvix-containers" "v0.7.1"]};
```
