13.3 New or Updated Modules

• New built-in module operator. While undocumented, the concept is real simply: operator.__add__(x, y) does exactly the same thing as x+y (for all types -- built-in, user-defined, extension-defined). As a convenience, operator.add does the same thing, but beware -- you can't use operator.and and a few others where the ``natural'' name for an operator is a reserved keyword. You can add a single trailing underscore in such cases.
• New built-in module errno. See the Library Reference Manual.
• Rewritten cgi module. See the Library Reference Manual.
• Improved restricted execution module (rexec). New module Bastion. Both are now documented in a new chapter on restricted execution in the Library Reference Manual.
• New string operations (all described in the Library Reference Manual): lstrip(), rstrip() (strip only the left/right whitespace), capitalize() (uppercase the first character, lowercase the rest), capwords() (capitalize each word, delimited a la string.split()), translate() (string transliteration - this existed before but can now also delete characters by specifying a third argument), maketrans() (a convenience function for creating translation tables for translate() and regex.compile()). The string function split() has an optional third argument which specifies the maximum number of separators to split; e.g. string.split('a=b=c', '=', 1) yields ['a', 'b=c']. (Note that for a long time, split() and splitfields() are synonyms.
• New regsub operations (see the Library Reference Manual): regsub.capwords() (like string.capwords() but allows you to specify the word delimiter as a regular expression), regsub.splitx() (like regsub.split() but returns the delimiters as well as the words in the resulting list). The optional maxsep argument is also supported by regsub.split().
• Module files pdb.py and profile.py can now be invoked as scripts to debug c.q. profile other scripts easily. For example: python /usr/local/lib/python1.4/profile.py myscript.py
• The os module now supports the putenv() function on systems where it is provided in the C library (Windows NT and most Unix versions). For example, os.putenv('PATH', '/bin:/usr/bin') sets the environment variable PATH to the string '/bin:/usr/bin'. Such changes to the environment affect subprocesses started with os.system(), os.popen() or os.fork() and os.execv(). When putenv() is supported, assignments to items in os.environ are automatically translated into corresponding calls to os.putenv(); however, calls to os.putenv() don't update os.environ, so it is actually preferable to assign to items of os.environ. For this purpose, the type of os.environ is changed to a subclass of UserDict.UserDict when os.putenv() is supported. (Buglet: os.execve() still requires a real dictionary, so it won't accept os.environ as its third argument. However, you can now use os.execv() and it will use your changes to os.environ!.)
• More new functions in the os module: mkfifo, plock, remove (== unlink), and ftruncate. See the Unix manual (section 2, system calls) for these function. More functions are also available under NT.
• New functions in the fcntl module: lockf() and flock() (don't ask :-)). See the Library Reference Manual.
• The first item of the module search path, sys.path[0], is the directory containing the script that was used to invoke the Python interpreter. If the script directory is not available (e.g. if the interpreter is invoked interactively or if the script is read from standard input), sys.path[0] is the empty string, which directs Python to search modules in the current directory first. Notice that the script directory is inserted before the entries inserted as a result of $PYTHONPATH. There is no longer an entry for the current directory later in the path (unless explicitly set in $PYTHONPATH or overridden at build time).