|Perl Language Reference Manual|
by Larry Wall and others
Paperback (6"x9"), 724 pages
RRP £29.95 ($39.95)
Sales of this book support The Perl Foundation! Get a printed copy>>>
Technically speaking, any extra semantics attached to a variable such
%SIG, or to any tied variable. Magical things happen when you diddle those variables.
- An increment operator that knows how to bump up alphabetics as well as numbers.
Special variables that have side effects when you access them or
assign to them. For example, in Perl, changing elements of the
%ENVarray also changes the corresponding environment variables that subprocesses will use. Reading the
$!variable gives you the current system error number or message.
- A file that controls the compilation of a program. Perl programs don't usually need a Makefile because the Perl compiler has plenty of self-control.
- The Unix program that displays online documentation (manual pages) for you.
- A "page" from the manuals, typically accessed via the man(1) command. A manpage contains a SYNOPSIS, a DESCRIPTION, a list of BUGS, and so on, and is typically longer than a page. There are manpages documenting commands, syscalls, library functions, devices, protocols, files, and such. In this book, we call any piece of standard Perl documentation (like perlop or perldelta) a manpage, no matter what format it's installed in on your system.
- See pattern matching.
- See instance variable.
- This always means your main memory, not your disk. Clouding the issue is the fact that your machine may implement virtual memory; that is, it will pretend that it has more memory than it really does, and it'll use disk space to hold inactive bits. This can make it seem like you have a little more memory than you really do, but it's not a substitute for real memory. The best thing that can be said about virtual memory is that it lets your performance degrade gradually rather than suddenly when you run out of real memory. But your program can die when you run out of virtual memory too, if you haven't thrashed your disk to death first.
- A character that is not supposed to be treated normally. Which characters are to be treated specially as metacharacters varies greatly from context to context. Your shell will have certain metacharacters, double-quoted Perl strings have other metacharacters, and regular expression patterns have all the double-quote metacharacters plus some extra ones of their own.
- Something we'd call a metacharacter except that it's a sequence of more than one character. Generally, the first character in the sequence must be a true metacharacter to get the other characters in the metasymbol to misbehave along with it.
- A kind of action that an object can take if you tell it to. See 16.
- The belief that "small is beautiful." Paradoxically, if you say something in a small language, it turns out big, and if you say it in a big language, it turns out small. Go figure.
- In the context of the stat syscall, refers to the field holding the permission bits and the type of the file.
- See statement modifier, regular expression modifier, and lvalue modifier, not necessarily in that order.
- A file that defines a package of (almost) the same name, which can either export symbols or function as an object class. (A module's main .pm file may also load in other files in support of the module.) See the use ( ) built-in.
- An integer divisor when you're interested in the remainder instead of the quotient.
- Short for Perl Monger, a purveyor of Perl.
- A temporary value scheduled to die when the current statement finishes.
- An array with multiple subscripts for finding a single element. Perl implements these using references--see "Manipulating Arrays of Arrays in Perl" (perllol) in Perl Tutorials and "Perl Data Structures Cookbook" (perldsc) in Perl Tutorials.
- The features you got from your mother and father, mixed together unpredictably. (See also inheritance, and single inheritance.) In computer languages (including Perl), the notion that a given class may have multiple direct ancestors or base classes.
|ISBN 9781906966027||Perl Language Reference Manual||See the print edition|