1.3 The Compulsory Features List

One way to describe a language is by listing its features. Of course, this will be more meaningful after you've seen Python in action; the best I can do now is speak in the abstract. And it's really how Python's features work together, that make it what it is. But looking at some of Python's attributes may help define it; Table 1-1 lists some of the common reasons cited for Python's appeal.

Table 1-1. Python Language Features

Features	Benefits
No compile or link steps	Rapid development cycle turnaround
No type declarations	Simpler, shorter, and more flexible programs
Automatic memory management	Garbage collection avoids bookkeeping code
High-level datatypes and operations	Fast development using built-in object types
Object-oriented programming	Code reuse, C++, Java, and COM integration
Embedding and extending in C	Optimization, customization, system "glue"
Classes, modules, exceptions	Modular "programming-in-the-large" support
A simple, clear syntax and design	Readability, maintainability, ease of learning
Dynamic loading of C modules	Simplified extensions, smaller binary files
Dynamic reloading of Python modules	Programs can be modified without stopping
Universal "first-class" object model	Fewer restrictions and special-case rules
Runtime program construction	Handles unforeseen needs, end-user coding
Interactive, dynamic nature	Incremental development and testing
Access to interpreter information	Metaprogramming, introspective objects
Wide interpreter portability	Cross-platform programming without ports
Compilation to portable bytecode	Execution speed, protecting source code
Standard portable GUI framework	Tkinter scripts run on X, Windows, and Macs
Standard Internet protocol support	Easy access to email, FTP, HTTP, CGI, etc.
Standard portable system calls	Platform-neutral system scripting
Built-in and third-party libraries	Vast collection of precoded software components
True open source software	May be freely embedded and shipped

To be fair, Python is really a conglomeration of features borrowed from other languages. It includes elements taken from C, C++, Modula-3, ABC, Icon, and others. For instance, Python's modules came from Modula, and its slicing operation from Icon (as far as anyone can seem to remember, at least). And because of Guido's background, Python borrows many of ABC's ideas, but adds practical features of its own, such as support for C-coded extensions.