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From a suggestion on c.l.py: modernize the introduction to the tutorial.
* Remove talk of shell scripting, replacing it by some more current examples * Mention C++ and Java as well as C Raymond H., please feel free to rewrite or revert as you see fit. If the changes are OK, they could be backported to the 2.4-maint branch.
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@ -72,35 +72,42 @@ Reference}.
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\chapter{Whetting Your Appetite \label{intro}}
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If you ever wrote a large shell script, you probably know this
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feeling: you'd love to add yet another feature, but it's already so
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slow, and so big, and so complicated; or the feature involves a system
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call or other function that is only accessible from C\ldots\ Usually
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the problem at hand isn't serious enough to warrant rewriting the
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script in C; perhaps the problem requires variable-length strings or
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other data types (like sorted lists of file names) that are easy in
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the shell but lots of work to implement in C, or perhaps you're not
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sufficiently familiar with C.
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If you do much work on computers, eventually you find that there's
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some task you'd like to automate. For example, you may wish to
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perform a search-and-replace over a large number of text files, or
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rename and rearrange a bunch of photo files in a complicated way.
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Perhaps you'd like to write a small custom database, or a specialized
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GUI application, or a simple game.
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Another situation: perhaps you have to work with several C libraries,
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and the usual C write/compile/test/re-compile cycle is too slow. You
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need to develop software more quickly. Possibly you've
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written a program that could use an extension language, and you don't
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want to design a language, write and debug an interpreter for it, then
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tie it into your application.
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If you're a professional software developer, you may have to work with
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several C/\Cpp/Java libraries but find the usual
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write/compile/test/re-compile cycle is too slow. Perhaps you're
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writing a test suite for such a library and find writing the testing
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code a tedious task. Or maybe you've written a program that could use
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an extension language, and you don't want to design and implement a
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whole new language for your application.
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In such cases, Python may be just the language for you. Python is
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simple to use, but it is a real programming language, offering much
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more structure and support for large programs than the shell has. On
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the other hand, it also offers much more error checking than C, and,
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being a \emph{very-high-level language}, it has high-level data types
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built in, such as flexible arrays and dictionaries that would cost you
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days to implement efficiently in C. Because of its more general data
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types Python is applicable to a much larger problem domain than
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\emph{Awk} or even \emph{Perl}, yet many things are at least as easy
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in Python as in those languages.
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Python is just the language for you.
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Python allows you to split your program in modules that can be
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You could write a {\UNIX} shell script or Windows batch files for some
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of these tasks, but shell scripts are best at moving around files and
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changing text data, not well-suited for GUI applications or games.
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You could write a C/{\Cpp}/Java program, but it can take a lot of
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development time to get even a first-draft program. Python is simpler
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to use, available on Windows, MacOS X, and {\UNIX} operating systems,
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and will help you get the job done more quickly.
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Python is simple to use, but it is a real programming language,
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offering much more structure and support for large programs than shell
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scripts or batch files can offer. On the other hand, Python also
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offers much more error checking than C, and, being a
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\emph{very-high-level language}, it has high-level data types built
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in, such as flexible arrays and dictionaries. Because of its more
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general data types Python is applicable to a much larger problem
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domain than Awk or even Perl, yet many things are at
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least as easy in Python as in those languages.
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Python allows you to split your program into modules that can be
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reused in other Python programs. It comes with a large collection of
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standard modules that you can use as the basis of your programs --- or
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as examples to start learning to program in Python. Some of these
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@ -115,8 +122,8 @@ programs, or to test functions during bottom-up program development.
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It is also a handy desk calculator.
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Python enables programs to be written compactly and readably. Programs
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written in Python are typically much shorter than equivalent C or
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\Cpp{} programs, for several reasons:
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written in Python are typically much shorter than equivalent C,
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\Cpp{}, or Java programs, for several reasons:
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\begin{itemize}
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\item
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the high-level data types allow you to express complex operations in a
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@ -145,7 +152,8 @@ it is encouraged!
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Now that you are all excited about Python, you'll want to examine it
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in some more detail. Since the best way to learn a language is
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to use it, you are invited to do so with this tutorial.
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to use it, the tutorial invites you to play with the Python interpreter
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as you read.
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In the next chapter, the mechanics of using the interpreter are
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explained. This is rather mundane information, but essential for
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