X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperl.pod;h=7291b847e8c93b27a02404f3df3d5048b04cd6d8;hb=ba58ab2683569fa823a7a9d7799f01b76d4cfe57;hp=c7b84520dfbf67eea94b177a21278dcda90f111c;hpb=f102b8834494e736221c17057fae0f964511ea18;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perl.pod b/pod/perl.pod index c7b8452..7291b84 100644 --- a/pod/perl.pod +++ b/pod/perl.pod @@ -4,66 +4,95 @@ perl - Practical Extraction and Report Language =head1 SYNOPSIS -B S<[ B<-sTuU> ]> - S<[ B<-hv> ] [ B<-V>[:I] ]> - S<[ B<-cw> ] [ B<-d>[:I] ] [ B<-D>[I] ]> - S<[ B<-pna> ] [ B<-F>I ] [ B<-l>[I] ] [ B<-0>[I] ]> - S<[ B<-I>I ] [ B<-m>[B<->]I ] [ B<-M>[B<->]I<'module...'> ]> - S<[ B<-P> ]> - S<[ B<-S> ]> - S<[ B<-x>[I] ]> - S<[ B<-i>[I] ]> - S<[ B<-e> I<'command'> ] [ B<--> ] [ I ] [ I ]...> - -For ease of access, the Perl manual has been split up into a number -of sections: - - perl Perl overview (this section) - perldelta Perl changes since previous version - perlfaq Perl frequently asked questions - - perldata Perl data structures - perlsyn Perl syntax - perlop Perl operators and precedence - perlre Perl regular expressions - perlrun Perl execution and options - perlfunc Perl builtin functions - perlvar Perl predefined variables - perlsub Perl subroutines - perlmod Perl modules: how they work - perlmodlib Perl modules: how to write and use - perlform Perl formats - perllocale Perl locale support - - perlref Perl references - perldsc Perl data structures intro - perllol Perl data structures: lists of lists - perltoot Perl OO tutorial - perlobj Perl objects - perltie Perl objects hidden behind simple variables - perlbot Perl OO tricks and examples - perlipc Perl interprocess communication - - perldebug Perl debugging - perldiag Perl diagnostic messages - perlsec Perl security - perltrap Perl traps for the unwary - perlstyle Perl style guide - - perlpod Perl plain old documentation - perlbook Perl book information - - perlembed Perl ways to embed perl in your C or C++ application - perlapio Perl internal IO abstraction interface - perlxs Perl XS application programming interface - perlxstut Perl XS tutorial - perlguts Perl internal functions for those doing extensions - perlcall Perl calling conventions from C +B S<[ B<-sTuU> ]> S<[ B<-hv> ] [ B<-V>[:I] ]> + S<[ B<-cw> ] [ B<-d>[:I] ] [ B<-D>[I] ]> + S<[ B<-pna> ] [ B<-F>I ] [ B<-l>[I] ] [ B<-0>[I] ]> + S<[ B<-I>I ] [ B<-m>[B<->]I ] [ B<-M>[B<->]I<'module...'> ]> + S<[ B<-P> ]> S<[ B<-S> ]> S<[ B<-x>[I] ]> + S<[ B<-i>[I] ]> S<[ B<-e> I<'command'> ] + [ B<--> ] [ I ] [ I ]...> + +For ease of access, the Perl manual has been split up into several +sections: + + perl Perl overview (this section) + perldelta Perl changes since previous version + perl5005delta Perl changes in version 5.005 + perl5004delta Perl changes in version 5.004 + perlfaq Perl frequently asked questions + perltoc Perl documentation table of contents + + perldata Perl data structures + perlsyn Perl syntax + perlop Perl operators and precedence + perlre Perl regular expressions + perlrun Perl execution and options + perlfunc Perl builtin functions + perlopentut Perl open() tutorial + perlvar Perl predefined variables + perlsub Perl subroutines + perlmod Perl modules: how they work + perlmodlib Perl modules: how to write and use + perlmodinstall Perl modules: how to install from CPAN + perlform Perl formats + perlunicode Perl unicode support + perllocale Perl locale support + + perlreftut Perl references short introduction + perlref Perl references, the rest of the story + perldsc Perl data structures intro + perllol Perl data structures: arrays of arrays + perlboot Perl OO tutorial for beginners + perltoot Perl OO tutorial, part 1 + perltootc Perl OO tutorial, part 2 + perlobj Perl objects + perltie Perl objects hidden behind simple variables + perlbot Perl OO tricks and examples + perlipc Perl interprocess communication + perlfork Perl fork() information + perlthrtut Perl threads tutorial + perllexwarn Perl warnings and their control + perlfilter Perl source filters + perldbmfilter Perl DBM filters + + perlcompile Perl compiler suite intro + perldebug Perl debugging + perldiag Perl diagnostic messages + perlnumber Perl number semantics + perlsec Perl security + perltrap Perl traps for the unwary + perlport Perl portability guide + perlstyle Perl style guide + + perlpod Perl plain old documentation + perlbook Perl book information + + perlembed Perl ways to embed perl in your C or C++ application + perlapio Perl internal IO abstraction interface + perlxs Perl XS application programming interface + perlxstut Perl XS tutorial + perlguts Perl internal functions for those doing extensions + perlcall Perl calling conventions from C + perlapi Perl API listing (autogenerated) + perlintern Perl internal functions (autogenerated) + + perltodo Perl things to do + perlhack Perl hackers guide + perlhist Perl history records + + perlamiga Perl notes for Amiga + perlcygwin Perl notes for Cygwin + perldos Perl notes for DOS + perlhpux Perl notes for HP-UX + perlos2 Perl notes for OS/2 + perlos390 Perl notes for OS/390 + perlvms Perl notes for VMS + perlwin32 Perl notes for Windows (If you're intending to read these straight through for the first time, the suggested order will tend to reduce the number of forward references.) -By default, all of the above manpages are installed in the +By default, the manpages listed above are installed in the F directory. Extensive additional documentation for Perl modules is available. The @@ -107,17 +136,17 @@ Perl combines (in the author's opinion, anyway) some of the best features of C, B, B, and B, so people familiar with those languages should have little difficulty with it. (Language historians will also note some vestiges of B, Pascal, and even -BASIC-PLUS.) Expression syntax corresponds quite closely to C +BASIC-PLUS.) Expression syntax corresponds closely to C expression syntax. Unlike most Unix utilities, Perl does not arbitrarily limit the size of your data--if you've got the memory, Perl can slurp in your whole file as a single string. Recursion is of -unlimited depth. And the tables used by hashes (previously called +unlimited depth. And the tables used by hashes (sometimes called "associative arrays") grow as necessary to prevent degraded -performance. Perl uses sophisticated pattern matching techniques to -scan large amounts of data very quickly. Although optimized for +performance. Perl can use sophisticated pattern matching techniques to +scan large amounts of data quickly. Although optimized for scanning text, Perl can also deal with binary data, and can make dbm files look like hashes. Setuid Perl scripts are safer than C programs -through a dataflow tracing mechanism which prevents many stupid +through a dataflow tracing mechanism that prevents many stupid security holes. If you have a problem that would ordinarily use B or B or @@ -128,140 +157,111 @@ scripts into Perl scripts. But wait, there's more... -Perl version 5 is nearly a complete rewrite, and provides -the following additional benefits: +Begun in 1993 (see L), Perl version 5 is nearly a complete +rewrite that provides the following additional benefits: -=over 5 +=over -=item * Many usability enhancements +=item * modularity and reusability using innumerable modules -It is now possible to write much more readable Perl code (even within -regular expressions). Formerly cryptic variable names can be replaced -by mnemonic identifiers. Error messages are more informative, and the -optional warnings will catch many of the mistakes a novice might make. -This cannot be stressed enough. Whenever you get mysterious behavior, -try the B<-w> switch!!! Whenever you don't get mysterious behavior, -try using B<-w> anyway. +Described in L, L, and L. -=item * Simplified grammar +=item * embeddable and extensible -The new yacc grammar is one half the size of the old one. Many of the -arbitrary grammar rules have been regularized. The number of reserved -words has been cut by 2/3. Despite this, nearly all old Perl scripts -will continue to work unchanged. +Described in L, L, L, L, +L, and L. -=item * Lexical scoping +=item * roll-your-own magic variables (including multiple simultaneous DBM implementations) -Perl variables may now be declared within a lexical scope, like "auto" -variables in C. Not only is this more efficient, but it contributes -to better privacy for "programming in the large". Anonymous -subroutines exhibit deep binding of lexical variables (closures). +Described in L and L. -=item * Arbitrarily nested data structures +=item * subroutines can now be overridden, autoloaded, and prototyped -Any scalar value, including any array element, may now contain a -reference to any other variable or subroutine. You can easily create -anonymous variables and subroutines. Perl manages your reference -counts for you. +Described in L. -=item * Modularity and reusability +=item * arbitrarily nested data structures and anonymous functions -The Perl library is now defined in terms of modules which can be easily -shared among various packages. A package may choose to import all or a -portion of a module's published interface. Pragmas (that is, compiler -directives) are defined and used by the same mechanism. +Described in L, L, L, and L. -=item * Object-oriented programming +=item * object-oriented programming -A package can function as a class. Dynamic multiple inheritance and -virtual methods are supported in a straightforward manner and with very -little new syntax. Filehandles may now be treated as objects. +Described in L, L, and L. -=item * Embeddable and Extensible +=item * compilability into C code or Perl bytecode -Perl may now be embedded easily in your C or C++ application, and can -either call or be called by your routines through a documented -interface. The XS preprocessor is provided to make it easy to glue -your C or C++ routines into Perl. Dynamic loading of modules is -supported, and Perl itself can be made into a dynamic library. +Described in L and L. -=item * POSIX compliant +=item * support for light-weight processes (threads) -A major new module is the POSIX module, which provides access to all -available POSIX routines and definitions, via object classes where -appropriate. +Described in L and L. -=item * Package constructors and destructors +=item * support for internationalization, localization, and Unicode -The new BEGIN and END blocks provide means to capture control as -a package is being compiled, and after the program exits. As a -degenerate case they work just like awk's BEGIN and END when you -use the B<-p> or B<-n> switches. +Described in L and L. -=item * Multiple simultaneous DBM implementations +=item * lexical scoping -A Perl program may now access DBM, NDBM, SDBM, GDBM, and Berkeley DB -files from the same script simultaneously. In fact, the old dbmopen -interface has been generalized to allow any variable to be tied -to an object class which defines its access methods. +Described in L. -=item * Subroutine definitions may now be autoloaded +=item * regular expression enhancements -In fact, the AUTOLOAD mechanism also allows you to define any arbitrary -semantics for undefined subroutine calls. It's not for just autoloading. +Described in L, with additional examples in L. -=item * Regular expression enhancements +=item * enhanced debugger and interactive Perl environment, with integrated editor support -You can now specify nongreedy quantifiers. You can now do grouping -without creating a backreference. You can now write regular expressions -with embedded whitespace and comments for readability. A consistent -extensibility mechanism has been added that is upwardly compatible with -all old regular expressions. +Described in L. -=item * Innumerable Unbundled Modules +=item * POSIX 1003.1 compliant library -The Comprehensive Perl Archive Network described in L -contains hundreds of plug-and-play modules full of reusable code. -See F for a site near you. - -=item * Compilability - -While not yet in full production mode, a working perl-to-C compiler -does exist. It can generate portable byte code, simple C, or -optimized C code. +Described in L. =back Okay, that's I enough hype. +=head1 AVAILABILITY + +Perl is available for most operating systems, including virtually +all Unix-like platforms. See L +for a listing. + =head1 ENVIRONMENT See L. =head1 AUTHOR -Larry Wall >, with the help of oodles of other folks. +Larry Wall , with the help of oodles of other folks. + +If your Perl success stories and testimonials may be of help to others +who wish to advocate the use of Perl in their applications, +or if you wish to simply express your gratitude to Larry and the +Perl developers, please write to perl-thanks@perl.org . =head1 FILES - "/tmp/perl-e$$" temporary file for -e commands "@INC" locations of perl libraries =head1 SEE ALSO a2p awk to perl translator - s2p sed to perl translator + http://www.perl.com/ the Perl Home Page + http://www.perl.com/CPAN the Comprehensive Perl Archive + =head1 DIAGNOSTICS -The B<-w> switch produces some lovely diagnostics. +The C pragma (and the B<-w> switch) produces some +lovely diagnostics. -See L for explanations of all Perl's diagnostics. +See L for explanations of all Perl's diagnostics. The C pragma automatically turns Perl's normally terse warnings +and errors into these longer forms. Compilation errors will tell you the line number of the error, with an indication of the next token or token type that was to be examined. -(In the case of a script passed to Perl via B<-e> switches, each +(In a script passed to Perl via B<-e> switches, each B<-e> is counted as one line.) Setuid scripts have additional constraints that can produce error @@ -275,8 +275,8 @@ switch? The B<-w> switch is not mandatory. Perl is at the mercy of your machine's definitions of various -operations such as type casting, atof(), and sprintf(). The latter -can even trigger a core dump when passed ludicrous input values. +operations such as type casting, atof(), and floating-point +output with sprintf(). If your stdio requires a seek or eof between reads and writes on a particular stream, so does Perl. (This doesn't apply to sysread() @@ -284,15 +284,16 @@ and syswrite().) While none of the built-in data types have any arbitrary size limits (apart from memory size), there are still a few arbitrary limits: a -given variable name may not be longer than 255 characters, and no -component of your PATH may be longer than 255 if you use B<-S>. A regular -expression may not compile to more than 32767 bytes internally. +given variable name may not be longer than 251 characters. Line numbers +displayed by diagnostics are internally stored as short integers, +so they are limited to a maximum of 65535 (higher numbers usually being +affected by wraparound). You may mail your bug reports (be sure to include full configuration -information as output by the myconfig program in the perl source tree, -or by C) to >. -If you've succeeded in compiling perl, the perlbug script in the utils/ -subdirectory can be used to help mail in a bug report. +information as output by the myconfig program in the perl source +tree, or by C) to perlbug@perl.com . If you've succeeded +in compiling perl, the B script in the F subdirectory +can be used to help mail in a bug report. Perl actually stands for Pathologically Eclectic Rubbish Lister, but don't tell anyone I said that.