Glimmer DSL Framework

Glimmer DSL for LibUI provides a prerequisite-free way to build native, platform-independent Ruby desktop applications. It uses libui (a thin C wrapper) to render native controls without the overhead of a JVM (unlike SWT). It is ideal for small, simple applications that need to start instantly and have a small memory footprint.

Features include:

• Declarative DSL syntax mapping to widget hierarchy.
• Bidirectional Data-Binding.
• Native-Executable packaging for Mac, Windows, and Linux.

require 'glimmer-dsl-libui'

include Glimmer

window('hello world').show

Glimmer is a Domain-Specific Language (DSL) Framework for Ruby that provides two core capabilities:

1. DSL Engine: Enables the creation of embedded internal DSLs within Ruby for various domains such as GUI, XML, or CSS.
2. Data-Binding Library: Provides tools to synchronize GUI elements with Model Attributes bidirectionally. As of v2, it supports the Shine data-binding syntax.

To use Glimmer's DSL capabilities, you must mix in the Glimmer module into your classes. This ensures that the DSL syntax is scoped to your class and does not pollute the global namespace.

You can declaratively wire GUI widgets to a Ruby object's attributes using the <=> operator. This automatically synchronizes the widget's state with the model.

Example using a combobox bound to a Person object's country attribute:

include Glimmer

class Person
  attr_accessor :country
  def initialize; @country = "Canada"; end
end

person = Person.new

root {
  combobox {
    text <=> [person, :country]
  }
}.open

In Glimmer DSL for Opal, you can use the bind method to create reactive UI elements. You can also define computed properties that automatically update when their dependencies change using the computed_by option.

Key binding patterns:

• bind(object, :attribute): Binds a widget property to an object attribute.
• bind(object, :computed_attr, computed_by: [:dep1, :dep2]): Binds to a method that recalculates whenever :dep1 or :dep2 changes.
• bind(object, :attribute, on_write: :type_conversion): Binds with an automatic type conversion on write (e.g., :to_i).

# Example of computed and type-converted binding
label {
  text bind(@contact, :name, computed_by: [:first_name, :last_name])
}

label {
  text bind(@contact, :age, on_write: :to_i, computed_by: [:year_of_birth])
}

The Glimmer DSL Engine allows you to mix multiple DSLs within a single application. This is achieved by detecting 'top-level keywords' (expressions denoted as TopLevelExpression).

When a top-level keyword from a specific DSL is encountered (e.g., html for XML or css for CSS), Glimmer automatically activates that DSL. Once the nested DSL block is finished, Glimmer automatically switches back to the previous DSL context. By default, all loaded DSL gems are enabled.

require 'glimmer-dsl-swt'
require 'glimmer-dsl-xml'
require 'glimmer-dsl-css'

include Glimmer

shell {
  browser {
    text html {
      head {
        style {
          css {
            h1 { background 'yellow' }
          }
        }
      }
      body { h1 { "Hello, World!" } }
    }
  }
}.open

Glimmer uses a Domain Specific Language (DSL) to define interfaces. A DSL expression typically consists of four components:

1. Keywords: The primary command (e.g., table).
2. Styles/Arguments: Optional arguments passed to a keyword (e.g., table(:multi) where :multi is a style).
3. Content: Nested properties, keywords, or listeners defined within a block (e.g., { table_column { text 'Name' } }).
4. Methods: Actions performed on objects (e.g., shell.show).

Example: Hello World in Glimmer DSL for SWT

include Glimmer

shell(:no_resize) { # keyword + style arg
  text "Glimmer" # attribute content

  label { # keyword content
    text "Hello, World!" # attribute content
  }
}.open

To run the Glimmer Calculator web version in a Rails environment:

1. Add the gem to your Gemfile without requiring it immediately:

   gem 'glimmer-cs-calculator', require: false

2. Require the launch module in your Rails asset pipeline:

   # In app/assets/javascripts/application.rb
   require 'glimmer-cs-calculator/launch'

3. Start your server with rails s and visit http://localhost:3000.

# Gemfile
gem 'glimmer-cs-calculator', require: false

# app/assets/javascripts/application.rb
require 'glimmer-cs-calculator/launch'

Glimmer DSL for Opal is an experimental web GUI adapter that allows you to run Glimmer desktop apps (built with glimmer-dsl-swt) in a web browser via Opal Ruby and Rails. It reuses the core Glimmer DSL engine, meaning desktop apps can be 'webified' without changing code and inherit full data-binding capabilities. Once running in the browser, apps can be styled using standard CSS.

To use this, install the glimmer-dsl-opal gem as described on its project page.

# Example: Adding a sample to a Rails app
# In app/assets/javascripts/application.rb
require 'samples/hello/hello_computed'