0.2 The Philosophy of Text Processing

Hang around any Python discussion groups for a little while, and you will certainly be dazzled by the contributions of the Python developer, Tim Peters (and by a number of other Pythonistas). His "Zen of Python" captures much of the reason that I choose Python as the language in which to solve most programming tasks that are presented to me. But to understand what is most special about text processing as a programming task, it is worth turning to Perl creator Larry Wall's cardinal virtues of programming: laziness, impatience, hubris.

What sets text processing most clearly apart from other tasks computer programmers accomplish is the frequency with which we perform text processing on an ad hoc or "one-shot" basis. One rarely bothers to create a one-shot GUI interface for a program. You even less frequently perform a one-shot normalization of a relational database. But every programmer with a little experience has had numerous occasions where she has received a trickle of textual information (or maybe a deluge of it) from another department, from a client, from a developer working on a different project, or from data dumped out of a DBMS; the problem in such cases is always to "process" the text so that it is usable for your own project, program, database, or work unit. Text processing to the rescue. This is where the virtue of impatience first appears we just want the stuff processed, right now!

But text processing tasks that were obviously one-shot tasks that we knew we would never need again have a habit of coming back like restless ghosts. It turns out that that client needs to update the one-time data they sent last month. Or the boss decides that she would really like a feature of that text summarized in a slightly different way. The virtue of laziness is our friend here with our foresight not to actually delete those one-shot scripts, we have them available for easy reuse and/or modification when the need arises.

Enough is not enough, however. That script you reluctantly used a second time turns out to be quite similar to a more general task you will need to perform frequently, perhaps even automatically. You imagine that with only a slight amount of extra work you can generalize and expand the script, maybe add a little error checking and some runtime options while you are at it; and do it all in time and under budget (or even as a side project, off the budget). Obviously, this is the voice of that greatest of programmers' virtues: hubris.

The goal of this book is to make its readers a little lazier, a smidgeon more impatient, and a whole bunch more hubristic. Python just happens to be the language best suited to the study of virtue.