Greg

Simple code generator

Introduction

Greg is a simple code generator. It generates code based on templates.

Usage

To create an app use the greg command as follows:

$ greg <app name> --template=<template name>

This will create your app on the current directory.

For example, to create a Roda application:

$ pwd
/tmp/code
$ ls
$ greg my_awesome_app --template=roda_app
Creating Project:
    [create] .env
    [create] routes/
    [create] routes/main.rb
    [create] spec/
    [create] spec/my_awesome_app/
    [create] spec/spec_helper.rb
    [create] spec/my_awesome_app_spec.rb
    [create] config.ru
    [create] Gemfile
    [create] public/
    [create] my_awesome_app.rb
    [create] views/
    [create] views/welcome.haml
    [create] views/layout.haml
    [create] assets/
    [create] assets/js/
    [create] assets/js/some_file.coffee
    [create] assets/css/
    [create] assets/css/some_file.scss
%
$ ls
my_awesome_app
$ ls my_awesome_app
assets  config.ru  Gemfile  my_awesome_app.rb  public  routes  spec  views
$

To get a list of templates you can use the --list flag

$ greg --list

To install a template (mus be listed under "Available templates" on the --list):

$ greg --install=<template name>

For example:

$ greg --install=roda_app

Creating you own template

The first thing you probably want to do is get some boilerplate in place:

$ greg my_template --template=template

This will create a new directory called my_template under ~/.greg_templates/. Inside, you'll find the my_template_generator.rb file. That's where all the logic for the generator goes.

Now you just need to define a method called #files, which should return an array containing all the needed files to be created.

The easiest way to get started is using Greg::FileTreeTemplate, like this:

class MyTemplateGenerator < Greg::Generator
  def files
    [
     Greg::FileTreeTemplate.new("templates"),
    ]
  end
end

And under ~/.greg_templates/my_template/templates/ put all the template files. This will compy the templates subdirectory almost verbatim to the generated application.

Notice I said "almost verbatim" and that's because we have an ace under our sleeves. Normally, we want to name files with some name different than just 'app.rb' or 'my_app.whatever'. In that case, instead of naming the file like that, you can use the @APP_NAME@ "variable". If you have the following tree:

~/.greg_templates/foo/templates/
├── @APP_NAME@.rb
└── spec
    ├── @APP_NAME@_spec.rb
    ├── @TEMPLATE_NAME@_spec.rb
    └── spec_helper.rb

When you run

$ greg my_cool_app --template=foo

the resulting tree will be:

~/.greg_templates/foo/templates/
├── my_cool_app.rb
└── spec
    ├── my_cool_app_spec.rb
    ├── foo_spec.rb
    └── spec_helper.rb

You also have some variables to use inside the file contents. The files will be rendered using ERB and you have the following methods available: (assuming the app name is again my_cool_app)

variable	exported value
app_name	my_cool_app
app_clas_name	MyCoolApp

Installation

You can install Greg by running

$ gem install greg

Contributing

1. Fork it ( https://github.com/[my-github-username]/greg/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request