Hi, Steve --
> What are the main organizational concepts in Lively? What are Areas,
> Workspaces, Packages and Classes?
> I am somewhat bemused by the way Javascript builds class-instance behaviour
> on top of a prototype system (although it's been a while since I read much
> about it, so I might be mistaken). Does Lively retain the idea of classes or
> is it purely a prototype system?
Modules
The main package entity for source cod in Lively is what we call a module. A
module integrates several things:
- It has a name and this name is used as a namespace when the module is loaded
- A module can be loaded asynchronously on demand simply by referencing them
with their name
- A module include class definitions (also function and object definitions but
we want to stick to the class concept whenever possible)
(Note: Since a module namespace can be currently extended from anywhere,
modules do not enforce encapsulation)
Module Example
module('lively.ide').requires('lively.Tools', 'lively.Ometa').toRun(function() {
// Code depending on lively.Tools and lively.Ometa
}); // end of module
This definition does two things:
a) Define the module lively.ide. The module can then be required from somewhere
else:
require('lively.ide').toRun(function() { new lively.ide.SystemBrowser().open()
})
Evaluating this will let the system:
1. Check if lively.ide is loaded. If not then the module name is translated to
an URL: {Config.codeBase}/lively/ide.js. That URL will be used to load the file
ide.js asynchronously. *
2. When the file is loaded run the code of toRun()
b) Define the namespace lively.ide.
That means that if the module is there you can access it's members in
JavaScript. For example the class lively.ide.SystemBrowser is such a member. **
For more information (module-file-mapping, how to get started in the wiki,
etc.) please read:
http://lists.hpi.uni-potsdam.de/archive/lively-kernel/2010-April/000347.html
http://lists.hpi.uni-potsdam.de/archive/lively-kernel/2010-April/000360.html
Classes
Lively implements it's own class system implementation that was inspired by
Prototype's class system.
e.g.
Object.subclass('Foo', {
method: function() { return 23 },
});
new Foo().method() // --> 23
IDE
Lively implements a complete JavaScript IDE, it's main part is the System code
browser. It can be opened using the WorldMenu.
> A friend suggested that Lively might be a good environment to learn
> Javascript but I'd like to have a better idea of how people manage
> dependencies among various libraries. It seems that managing a pool of *.js
> files also needs to represented. Does Lively let you mix and match other
> Javascript libraries? If so, would it be possible to add visual tools to help
> with this or is the fundamental browser model too restrictive for that?
It's definitely better to learn JavaScript in Lively than using in-place HTML
scripting since Lively gives you immediate feedback (evaluate any expression in
a Workspace or any other TextMorph with CMD+d (CMD+p to print the result).
Managing files: see modules.
Best,
Robert_______________________________________________
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