Subs

A lightweight alternative to Ruby gems

Overview

There are often cases when a developer/team needs to reuse and share portions of code which just "aren't enough" for a gem. Subs might be a solution to this problem. Read on.

The name "subs", the concept of subs, the technology behind subs are yet experimental. All sorts of feedback is highly appreciated.

Examples of subs

A library or extension in its early stage of existence with a high reuse potential.
A low-level extension to a class which implements a particular pattern, which isn't enough for a gem. Examples: boilerplate initializer, attribute validation, attribute caching etc.

Sub features

Subs are truly lightweight.
Subs don't have version numbers.
Subs don't have init code. They won't gain control until you require them.
The amount of formalities required to update a sub is almost zero.
There is no minimum amount of code required to make a sub. If your extension is 1 line long, but is reusable — go make a sub of it.
Subs do have home repositories, but updates to subs are made directly in the projects which use them.
Sub's home repository is checked out to N locations simultaneously.
After you've made an update to the sub commit your changes right away to the sub's origin.
Underlying mechanism to manage the distribution of subs is Git submodules.
Subs are often local to developer/team which produced them.
Subs don't require unique names like gems do. It's okay to name your sub downloader if you can uniquely identify what it is.
Subs have 100% test coverage. This is to compensate for their highly dynamic and version-free nature.

Setup

Consider you are in the local working copy of your project and you want to install a sub from https://github.com/dadooda/feature_cache into it. Steps follow.

Create a directory for subs:
```
$ mkdir -p vendor/subs
```

Check out the sub as Git submodule:

$ git submodule add git@github.com:dadooda/feature_cache.git vendor/subs/feature_cache

Add the $: include path update to your boot code. E.g. in your config/boot.rb do a:

Dir[File.expand_path("../../vendor/subs/*/lib", __FILE__)].each {|fn| $: << fn if File.directory?(fn)}

To use the sub in your code do a:
```
require "feature/cache"
```
To install/update all installed subs to their latest versions, do a:
```
$ git submodule update --init --remote
```

dadooda/subs

Subs

Overview

Examples of subs

Sub features

Setup

Further reading

Cheers!