# Glimmer (The Original One And Only)
[![Coverage Status](https://coveralls.io/repos/github/AndyObtiva/glimmer/badge.svg?branch=master)](https://coveralls.io/github/AndyObtiva/glimmer?branch=master)

Glimmer is a cross-platform Ruby desktop development library. Glimmer's main innovation is a JRuby DSL that enables easy and efficient authoring of desktop application user-interfaces while relying on the robust platform-independent Eclipse SWT library. Glimmer additionally innovates by having built-in desktop UI data-binding support to greatly facilitate synchronizing the UI with domain models. As a result, that achieves true decoupling of object oriented components, enabling developers to solve business problems without worrying about UI concerns, or alternatively drive development UI-first, and then write clean business components test-first afterward.

You may learn more by reading this article: [Eclipse Zone Tutorial](http://eclipse.dzone.com/articles/an-introduction-glimmer)

## Example

Code (`hello_world.rb`):
```ruby
include Glimmer

shell {
  text "Glimmer"
  label {
    text "Hello World!"
  }
}.open
```

Run:
```
glimmer hello_world.rb
```

Glimmer app:

![Glimmer](https://github.com/AndyObtiva/glimmer/raw/master/images/glimmer-hello-world.png)


## Resources

* [Eclipse Zone Tutorial](http://eclipse.dzone.com/articles/an-introduction-glimmer)
* [InfoQ Article](http://www.infoq.com/news/2008/02/glimmer-jruby-swt)
* [RubyConf 2008 Video](https://confreaks.tv/videos/rubyconf2008-desktop-development-with-glimmer)
* [Code Blog](http://andymaleh.blogspot.com/search/label/Glimmer)

## Background

Ruby is a dynamically-typed object-oriented language, which provides great productivity gains due to its powerful expressive syntax and dynamic nature. While it is proven by the Ruby on Rails framework for web development, it currently lacks a robust platform-independent framework for building desktop applications. Given that Java libraries can now be utilized in Ruby code through JRuby, Eclipse technologies, such as SWT, JFace, and RCP can help fill the gap of desktop application development with Ruby.

## Platform Support

Glimmer runs on the following platforms:
- Mac
- Windows
- Linux

## Pre-requisites

* Java SE Runtime Environment 7 or higher (find at https://www.oracle.com/java/technologies/javase-downloads.html)
* JRuby 9.2.10.0 (supporting Ruby 2.5.x syntax) (find at https://www.jruby.org/download)

On **Mac** and **Linux**, an easy way to obtain JRuby is through [RVM](http://rvm.io) by running:

```bash
rvm install jruby-9.2.10.0
```

## Setup

Please follow these instructions to make the `glimmer` command available on your system.

### Option 1: Direct Install

Run this command to install directly:
```
jgem install glimmer -v 0.2.0
```

### Option 2: Bundler

Add the following to `Gemfile`:
```
gem 'glimmer', '~> 0.2.0'
```

And, then run:
```
bundle install
```

## Glimmer command

Usage:
```
glimmer application.rb
```

Runs a Glimmer application using JRuby, automatically preloading
the glimmer ruby gem and SWT jar dependency.

Example:
```
glimmer hello_world.rb
```
This runs the Glimmer application hello_world.rb

## Glimmer DSL Syntax

### Widgets

Glimmer UIs (user interfaces) are modeled with widgets (wrappers around the SWT library widgets found here: https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0).

In Glimmer DSL, widgets are declared with lowercase underscored naming (you may look at usage examples in the `samples` directory).

The `shell` widget is always the outermost widget containing all others in a desktop windowed application.

Other widget examples:
- `button`: wrapper for `org.eclipse.swt.widgets.Button`
- `label`: wrapper for `org.eclipse.swt.widgets.Label`
- `tab_folder`: wrapper for `org.eclipse.swt.widgets.TabFolder`
- `tab_item`: wrapper for `org.eclipse.swt.widgets.TabItem`
- `table`: wrapper for `org.eclipse.swt.widgets.Table`
- `table_column`: wrapper for `org.eclipse.swt.widgets.TableColumn`
- `tree`: wrapper for `org.eclipse.swt.widgets.Tree`

### Widget Properties

Widget properties (e.g. `text`) may be set with methods matching their names in lower snakecase.

Widget property examples:
- `text` to set text value of a `label`
- `gridData` to set grid data of a `composite`

### Data-Binding

Data-binding is done with `bind` command following widget property to bind and taking model and bindable attribute as arguments.

Data-binding examples:
- `text bind(contact, :first_name)`
- `text bind(contact, 'address.street')`
- `text bind(contact, :name, computed_by: [:first_name, :last_name])`

The first example binds the text property of a widget like `label` to the first name of a contact model.

The second example binds the text property of a widget like `label` to the nested street of
the address of a contact. This is called nested property data binding.

The third example demonstrates computed value data binding whereby the value of `name` depends on changes to both `first_name` and `last_name`

You may learn more about Glimmer's syntax by reading the Eclipse Zone Tutorial mentioned in resources and opening up the samples under the `samples` folder.

## Samples

Check the "samples" folder for examples on how to write Glimmer applications. To run them, make sure to install the `glimmer` gem first and then use the `glimmer` command.

Example:

```
glimmer samples/hello_world.rb
```

## SWT Reference

https://www.eclipse.org/swt/docs.php

Here is a list of SWT widgets:

https://help.eclipse.org/2019-12/topic/org.eclipse.platform.doc.isv/guide/swt_widgets_controls.htm?cp=2_0_7_0_0


## Girb (Glimmer irb)

With Glimmer installed, you may run want to run `girb` instead of standard `irb` to have SWT preloaded and the Glimmer library required and included for quick Glimmer coding/testing.

## Logging

Glimmer comes with a Ruby Logger accessible via `Glimmer.logger`
Its level of logging defaults to `Logger::WARN`
It may be configured to show a different level of logging as follows:
```ruby
Glimmer.logger.level = Logger::DEBUG
```
This results in more verbose debugging log to `STDOUT`, which is helpful in troubleshooting Glimmer DSL syntax when needed.

Example log:
```
D, [2017-07-21T19:23:12.587870 #35707] DEBUG -- : method: shell and args: []
D, [2017-07-21T19:23:12.594405 #35707] DEBUG -- : ShellCommandHandler will handle command: shell with arguments []
D, [2017-07-21T19:23:12.844775 #35707] DEBUG -- : method: composite and args: []
D, [2017-07-21T19:23:12.845388 #35707] DEBUG -- : parent is a widget: true
D, [2017-07-21T19:23:12.845833 #35707] DEBUG -- : on listener?: false
D, [2017-07-21T19:23:12.864395 #35707] DEBUG -- : WidgetCommandHandler will handle command: composite with arguments []
D, [2017-07-21T19:23:12.864893 #35707] DEBUG -- : widget styles are: []
D, [2017-07-21T19:23:12.874296 #35707] DEBUG -- : method: list and args: [:multi]
D, [2017-07-21T19:23:12.874969 #35707] DEBUG -- : parent is a widget: true
D, [2017-07-21T19:23:12.875452 #35707] DEBUG -- : on listener?: false
D, [2017-07-21T19:23:12.878434 #35707] DEBUG -- : WidgetCommandHandler will handle command: list with arguments [:multi]
D, [2017-07-21T19:23:12.878798 #35707] DEBUG -- : widget styles are: [:multi]
```

## Raw JRuby Command

If there is a need to run Glimmer directly via the `jruby` command, you
may run the following:

```
jruby -J-classpath "path_to/swt.jar" -r glimmer -S application.rb
```

The `-J-classpath` option specifies the `swt.jar` file path, which can be a
manually downloaded version of SWT, or otherwise the one included in the gem. You can lookup the one included in the gem by running `jgem which glimmer` to find the gem path and then look through the `vendor` directory.

The `-r` option preloads (requires) the `glimmer` library in Ruby.

The `-S` option specifies a script to run.

### Mac Support

Mac is well supported with the `glimmer` command. However, if there is a reason to use the raw jruby command, you need to pass an extra option (`-J-XstartOnFirstThread`) to JRuby on the Mac.

Example:
```
jruby -J-XstartOnFirstThread -J-classpath "path_to/swt.jar" -r glimmer -S application.rb
```

## Feature Suggestions

These features have been suggested. You might see them in a future version of Glimmer. You are welcome to contribute more feature suggestions.

- **Nested indexed property data binding**: a complementary feature to nested property data binding that binds to a collection element by index (e.g. `bind(user, 'addresses[1].street')`)
- **bind_collection**: an iterator that enables spawning widgets based on a variable collection (e.g. `bind_collection('user.addresses') { |address| address_widget {...} }` spawns 3 `AddressWidget`s if `user.addresses` is set with 3 addresses; and replaces with 2 `AddressWidget`s if `user.addresses` is reset with 2 addresses only). Needs further thought on naming and functionality.

## Contributors

* Andy Maleh (Founder)
* Dennis Theisen

## License

Copyright (c) 2007-2020 Andy Maleh.
See LICENSE.txt for further details.