Datasheet

Part I: Introduction to Python Frameworks

Web 2.0 Capability Description

Leveraging industry-wide

display standards (HTML,

Flex, and JavaScript)

This means that you can erase phrases such as Windows Foundation

Classes (WFCs), Cocoa, and Abstract Window Toolkit (AWT) from

your memory.

Leveraging a common data

format (XML or JSON)

This means that data sharing among applications is straight-

forward.

Leveraging high-speed

networking

This makes running Web 2.0 applications generally as seamless as

running desktop applications.

Platform-independent

development

Writing to a standard that is above the platform level means that

you can develop applications without having to worry about

which operating systems, browsers, and so on they will run on

(with caveats).

The Role of AJAX in Web 2.0

The ability to make an asynchronous call to a URL and have the data return handled by code within the

browser is key to creating the RIA experience for the user. Without AJAX ( Asynchronous JavaScript and

XML ), browser-resident RIAs would not be feasible for the reasons discussed previously. Additionally,

not only can AJAX make asynchronous external method calls (out from the browser), but it can also make

internal method calls (within the browser). The latter capability is the basis for providing changes in

visual elements within the RIA, including special effects like growing and shrinking areas, tabbed pages,

and drag and drop.

As good and as useful as AJAX is in this regard, the fact is that AJAX must be implemented in JavaScript,

and that is the source of a good deal of pain for the developer. Although JavaScript has only recently

been taken seriously as a development language, its idiosyncrasies and tendency to be broken in differ-

ent ways in different browsers is a constant source of consternation to developers and end users alike.

Even in a nonbroken world though, it’s great to have a level of abstraction sitting atop JavaScript.

Fortunately, MochiKit and other libraries are there to help.

MochiKit is covered specifically in Chapter 11 , but you will find code snippets and explanations of its

use in other chapters in this book.

Leveraging the Power of DSL s

Domain-specific languages ( DSL s) are limited computer languages designed for a specific class of problem.

However, using a special-purpose language that’s really good at creating solutions in a specific

problem domain is not a brand-new idea. Developers have been creating special syntaxes in languages

since way back when, especially in the bygone heyday of early work in Lisp (list processing) and artifi-

cial intelligence. In Python and one or two other languages classified as scripting languages, creating a

special syntax on top of the basic language becomes a highly tractable problem.