pesy: Native Reason Project from Json.

Use package.json to automatically configure libraries and executables built with Dune.

Commands:

• pesy : Creates a new project in the current directory.
• esy : Builds the current project (just like every other esy project).
• esy pesy : Updates your build config from package.json (run this any time you change package.json).

pesy (Create New Project)

pesy global command creates esy projects instantly inside of any directory.

npm install -g pesy

cd my-project
pesy      # Hit enter to accept default name

This creates:

• package.json with useful dependencies/compilers.
• .gitignore and README.md with instructions for new contributors.
• .circleci continuous integration with cache configured for ultra-fast pull requests.
• library/, executable/ and test/ directory with starter modules.

esy (Build The Project)

Just like with any esy project, running esy from the project directory will build it and fetch/install any dependencies you might need.

esy

Your project's esy.build field is set to pesy, which will run pesy to verify that all your build config is up to date before invoking the Dune build. It will let you know if you need to run esy pesy to update your build config from new changes to package.json.

esy pesy: (Update Build Config Based On package.json)

esy pesy

If you change your buildDirs config in package.json, run this command to update build configuration based on your latest package.json. If you forget to run this command and try to build (by running esy) without first running esy pesy, the build will remind you.

Configuring:

Configure your package.json's buildDirs field for multiple libraries and executables. buildDirs.DirectoryName means that a library or executable will be located at ./DirectoryName. The buildDirs.DirectoryName.name field determines the public name of the library or executable. a name ending in .exe is automatically configured as an executable, and a name of the form packageName.anything is automatically configured to be a library with the public name of packageName.anything.

"buildDirs": {
  "MyLibrary": {
    "name": "packageNameMyLibrary",
    "namespace": "MyLibrary",
    "require": ["console.lib"]
  },
  "Tests": {
    "name": "Tests.exe",
    "description": "Runs all the tests natively",
    "flags": ["-linkall"],
    "require": ["console.lib", "packageNameMyLibrary""]
  }
}

Supported Config

Not all config is supported. This is just a proof of concept. If you'd like to add support for more config fields, PRs are welcomed.

Binaries

Libraries

Both Libraries And Binaries

Consuming New Package And Library Dependencies:

• Add dependencies to dependencies in package.json.

• Add the name of that new dependencies library to package.json's buildDirs section that you want to use the library within. For example, if your project builds a library in the exampleLib/ directory, and you want it to depend on a library named bos.top from an opam package named bos, change the package.json to look like this:

  {
    "name": "my-package",
    "dependencies": {
      "@opam/bos": "*"
    },
    "buildDirs": {
      "exampleLib": {
        "namespace": "Examples",
        "name": "my-package.example-lib",
        "require": [ "bos.top" ]
      }
    }
  }

• Then run:

  esy install  # Fetch dependency sources
  esy pesy     # Configure the build based on package.json
  esy build    # Do the build

Note: After adding/building a new dependency you can use esy ls-libs to see which named libraries become available to you by adding the package dependency.

Tradeoffs:

esy-pesy is good for rapidly making new small executables/libraries. Once they grow, you'll want to "eject out" of esy-pesy and begin customizing using a more advanced build system.

Adding pesy to an existing project.

You probably don't need pesy if you have an existing project that is working well, but to add pesy to an existing project, follow these steps:

1. Add a dependency on pesy, and configure buildDirs:

{
  "name": "my-package",
  "dependencies": {
    "pesy": "*"
  },
  "buildDirs": {
    "exampleLib": {
      "namespace": "Examples",
      "name": "my-package.example-lib",
      "require": [ "bos.top" ]
    },
    "bin": {
      "name": "my-package.exe",
      "require": [
        "my-package.lib"
      ]
    }
  }
}

2.Install and Build:

esy install
esy pesy  # Generate the project build config from json
esy build

Future Development:

The next major version of pesy is getting even simpler and better, and has undergone a full native rewrite.

Follow the work in its new repo: https://github.com/esy/pesy.

Changes:

version 0.4.3 (6/20/2019) Moved pesy to a devDependency of all newly created projects. Also did the same for refmterr. This causes fewer package conflicts.

version 0.4.2 (6/16/2019)

Make new projects pin to ocaml 4.7.1004 so that it compiles with Reason, since we're still waiting on Reason to work with 4.8.

version 0.4.0 (12/21/2018)

• Allow buildDirs to contain deeper directories such as "path/to/my-lib": {...}".
• Added support for wrapped property on libraries.
• Added support for virtualModules and implements - properties for Dune virtual libraries. (This will only be supported if you mark your project as Dune 1.7 - not yet released).
• Stopped using ignore_subdirs in new projects, instead using (dirs (:standard \ _esy)) which only works in Dune 1.6.0+, so made new projects have a lower bound of Dune 1.6.0.
• Support new properties rawBuildConfig which will be inserted at the bottom of the target being configured (library/executable).
  • It expects an array of strings, each string being a separate line in the generated config.
• Support new properties rawBuildConfigFooter which will be inserted at the bottom of the entire Dune file for the target being configured.
  • It expects an array of strings, each string being a separate line in the generated config.
• Support new properties modes for binaries and libraries list(string).