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| -rw-r--r-- | Doc/tut/tut.tex | 72 |
1 files changed, 40 insertions, 32 deletions
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index e3cb1de..e0c54b4 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -72,35 +72,42 @@ Reference}. \chapter{Whetting Your Appetite \label{intro}} -If you ever wrote a large shell script, you probably know this -feeling: you'd love to add yet another feature, but it's already so -slow, and so big, and so complicated; or the feature involves a system -call or other function that is only accessible from C\ldots\ Usually -the problem at hand isn't serious enough to warrant rewriting the -script in C; perhaps the problem requires variable-length strings or -other data types (like sorted lists of file names) that are easy in -the shell but lots of work to implement in C, or perhaps you're not -sufficiently familiar with C. - -Another situation: perhaps you have to work with several C libraries, -and the usual C write/compile/test/re-compile cycle is too slow. You -need to develop software more quickly. Possibly you've -written a program that could use an extension language, and you don't -want to design a language, write and debug an interpreter for it, then -tie it into your application. - -In such cases, Python may be just the language for you. Python is -simple to use, but it is a real programming language, offering much -more structure and support for large programs than the shell has. On -the other hand, it also offers much more error checking than C, and, -being a \emph{very-high-level language}, it has high-level data types -built in, such as flexible arrays and dictionaries that would cost you -days to implement efficiently in C. Because of its more general data -types Python is applicable to a much larger problem domain than -\emph{Awk} or even \emph{Perl}, yet many things are at least as easy -in Python as in those languages. - -Python allows you to split your program in modules that can be +If you do much work on computers, eventually you find that there's +some task you'd like to automate. For example, you may wish to +perform a search-and-replace over a large number of text files, or +rename and rearrange a bunch of photo files in a complicated way. +Perhaps you'd like to write a small custom database, or a specialized +GUI application, or a simple game. + +If you're a professional software developer, you may have to work with +several C/\Cpp/Java libraries but find the usual +write/compile/test/re-compile cycle is too slow. Perhaps you're +writing a test suite for such a library and find writing the testing +code a tedious task. Or maybe you've written a program that could use +an extension language, and you don't want to design and implement a +whole new language for your application. + +Python is just the language for you. + +You could write a {\UNIX} shell script or Windows batch files for some +of these tasks, but shell scripts are best at moving around files and +changing text data, not well-suited for GUI applications or games. +You could write a C/{\Cpp}/Java program, but it can take a lot of +development time to get even a first-draft program. Python is simpler +to use, available on Windows, MacOS X, and {\UNIX} operating systems, +and will help you get the job done more quickly. + +Python is simple to use, but it is a real programming language, +offering much more structure and support for large programs than shell +scripts or batch files can offer. On the other hand, Python also +offers much more error checking than C, and, being a +\emph{very-high-level language}, it has high-level data types built +in, such as flexible arrays and dictionaries. Because of its more +general data types Python is applicable to a much larger problem +domain than Awk or even Perl, yet many things are at +least as easy in Python as in those languages. + +Python allows you to split your program into modules that can be reused in other Python programs. It comes with a large collection of standard modules that you can use as the basis of your programs --- or as examples to start learning to program in Python. Some of these @@ -115,8 +122,8 @@ programs, or to test functions during bottom-up program development. It is also a handy desk calculator. Python enables programs to be written compactly and readably. Programs -written in Python are typically much shorter than equivalent C or -\Cpp{} programs, for several reasons: +written in Python are typically much shorter than equivalent C, +\Cpp{}, or Java programs, for several reasons: \begin{itemize} \item the high-level data types allow you to express complex operations in a @@ -145,7 +152,8 @@ it is encouraged! Now that you are all excited about Python, you'll want to examine it in some more detail. Since the best way to learn a language is -to use it, you are invited to do so with this tutorial. +to use it, the tutorial invites you to play with the Python interpreter +as you read. In the next chapter, the mechanics of using the interpreter are explained. This is rather mundane information, but essential for |