6 Chapter 1: A Python Q&A Session
So, is Python a scripting language or not? It depends on whom you ask. In general, the
term "scripting" is probably best used to describe the rapid and flexible mode of development
that Python supports, rather than a particular application domain.
OK, but What's the Downside?
After using it for 21 years, writing about it for 18, and teaching it for 16, I've found that
the only significant universal downside to Python is that, as currently implemented, its
execution speed
may not always be as fast as that of fully compiled and lower-level
languages such as C and C++. Though relatively rare today, for some tasks you may
still occasionally need to get "closer to the iron" by using lower-level languages such
as these that are more directly mapped to the underlying hardware architecture.
We'll talk about implementation concepts in detail later in this book. In short, the
standard implementations of Python today compile (i.e., translate) source code statements
to an intermediate format known as byte code
and then interpret the byte code.
Byte code provides portability, as it is a platform-independent format. However, because
Python is not normally compiled all the way down to binary machine code (e.g.,
instructions for an Intel chip), some programs will run more slowly in Python than in
a fully compiled language like C. The PyPy
system discussed in the next chapter can
achieve a 10X to 100X speedup on some code by compiling further as your program
runs, but it's a separate, alternative implementation.