From smalltalk to javascript and back

Smalltalk ♥ JavaScript

Amber maps one to one with the JavaScript equivalent:

• String ⇔ String
• Number ⇔ Number
• BlockClosure ⇔ function
• Dictionary ⇔ Object
• Error ⇔ Error
• etc.

Referencing JavaScript Objects from Smalltalk

You can easily access JavaScript objects directly from Amber and access their properties or call functions:

1. someUser.name becomes someUser name
2. someUser.name = "John" becomes someUser name: 'John'
3. console.log('hello world') becomes console log: 'hello world'
4. window.jQuery('foo').css('background', 'red') becomes (window jQuery: 'foo') css: 'background' color: 'red'

For keyword selectors, only the first keyword matters, all the other keywords will be ignored. That means our previous example could have been: (window jQuery: 'foo') css: 'background' set: 'red'

Note that you can inspect, print, etc javaScript objects from Amber. For example, you can inspect the window object.

Referencing Smalltalk Objects from JavaScript

Amber also makes it easy to send messages to Smalltalk objects from JavaScript:

1. Unary messages begin with an underscore: yourself becomes _yourself()
2. Binary messages are prefixed with 2 underscores: 3@4 becomes (3).__at(4)
3. Keyword messages follow the same rules as unary messages but with single underscores and a final underscore: aDictionary at: 3 put: 4 becomes aDictionary._at_put_(3, 4)

Smalltalk classes are added to the global smalltalk JavaScript object: Object new becomes smalltalk.Object._new();.

A Smalltalk instance variable is accessed from within JavaScript as self['@name'].