enso/docs/distribution/packaging.md

layout	title	category	tags	order
developer-doc	Enso Libraries Packaging	distribution	packaging distribution layout	2

Enso Libraries Packaging

Given the nature of Enso as an open-source programming language and platform, it is crucial that we provide users with an extensible package management system. This document describes the current state of our packaging efforts, as well as future directions and enhancements to it.

• Enso Package Structure
  • The src Directory
  • The polyglot Directory
  • The package.yaml File
  • The visualization Directory
• Build Reproducibility

Enso Package Structure

The general directory structure of an Enso package is as follows:

My_Package
├── package.yaml
├── polyglot
│   ├── java
│   │   └── jar.jar
│   └── js
│       └── library.js
├── src
│   ├── Main.enso
│   └── Sub_Module
│       ├── Helper.enso
│       └── Util.enso
└── visualization (optional)
    └── 

The src Directory

The src directory contains all Enso sources, organized in a hierarchical structure. The structure of this directory dictates how particular modules are imported in all of Enso code.

Note that all files and directories in this subtree must be named according to the Enso style for referent names (i.e. Upper_Snake_Case, see the syntax specification).

A file located at the path My_Package/src/Sub_Module/Helper.enso will be imported like so:

import My_Package.Sub_Module.Helper

Please note the following:

• The name of the package appears as the first segment of the name.
• The package name is not specified by the containing directory's name, but rather it is described in the package.yaml file.

The exact transformation is as follows:

1. The name of the package becomes the first segment of the qualified module name.
2. Any subdirectories on the path from the src directory to the source file are appended as consecutive segments.
3. The name of the source file, with the .enso extension stripped, becomes the last segment.

The polyglot Directory

The polyglot directory contains per-language subdirectories containing files used by the supported polyglot languages. The contents of each subdirectory is specified on a per-language basis, in the polyglot documentation.

The package.yaml File

package.yaml describes certain package metadata, such as its name, authors and version. It also includes the list of extra dependencies of the package (dependencies that are not present in the resolver or need a version override). The following is an example of this manifest file.

license: MIT
name: My_Package
version: 1.0.1
author: "John Doe <john.doe@example.com>"
maintainer: "Jane Doe <jane.doe@example.com>"
resolver: lts-1.2.0
extra-dependencies:
  - name: Base
    version: "1.2.0"
  - name: Http
    version: "4.5.3"

The following is the specification of the manifest fields. Fields marked as Optional (required for publishing) are completely optional during development - if not specified, their default values will be used. However, they must be specified before publishing the package. A package missing any of these fields cannot be published.

license

Optional (required for publishing) String: The short license name of this package. Defaults to None, meaning the package is not safe for use by third parties.

version

Optional (required for publishing) String: The semantic versioning string, in the major.minor.patch format. If not set, it defaults to dev (which can be used for development, but is not a valid version for publishing).

author

Optional String or List of Strings: The name(s) and contact info(s) of the author(s) of this library, in the Name <contact> or Name format.

maintainer

Optional String or List of Strings: The name(s) and contact info(s) of the current maintainer(s) of this library, in the Name <contact> or Name format.

resolver

Note This field is not currently implemented. Optional (required for publishing) String: The resolver name, used to choose compiler version and basic libraries set. If not set, the system-default resolver will be used.

The actionables for this section are:

• Extend the compiler version to handle version bounds.

extra-dependencies

Note This field is not currently implemented. Optional List of Library objects: The list of libraries this package requires to function properly and that are not included in the resolver. Defaults to an empty list.

A library object is of the form:

name: <name of the library>
version: <semver string of the required library version>

The actionables for this section are:

• Extend the library version field to handle version bounds.

The visualization Directory

As Enso is a visual language, a package may contain a specification of how data can be displayed in various tools, for example Enso IDE. The Enso package structure may optionally contain a visualization directory which may contain visualization definitions.

For more information on how visualization definitions should work with the Enso IDE, see this example.

Build Reproducibility

It is crucial for any good development environment to provide reproducible builds, such that it is impossible for it to go wrong by mismatching library versions.

The actionables for this section are:

• Decide on the strategies of ensuring consistent library resolution. This may include hashing the downloaded versions of libraries and publishing stack-style resolvers for sets of libraries that are proven to work well together.