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<TITLE>Glossary</TITLE>

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<H1><FONT SIZE=6 COLOR=#FF0000>Glossary</FONT></H1>

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<P>

<B>action</B> Any task initiated in a script.

<P>

<B>actual arguments</B> The scalar values that are supplied to

a subroutine by the programmer when it is called. When &amp;boxer(glove)

is called, 'glove' is the actual argument.

<P>

<B>address operator</B> A language construct for manipulating

the actual location of an object in the computer's memory. Not

needed in Perl.

<P>

<B>alternatives</B> In Perl, the term refers to alternatives with

regular expressions. They are separated with a single bar: |.

 Normal Perl expressions are separated with two bars: ||.

<P>

<B>architecture</B> The &quot;kind&quot; of computer used, where

&quot;kind&quot; refers to all the computers that can run the

same binary code. Perl isn't fussy about architecture, whereas

C is.

<P>

<B>argument</B> Data supplied as input to a function, subroutine,

or program when the data is asked for. Also called a <I>parameter</I>.

<P>

<B>ARGV</B> The name of the array that contains the argument 'vector'

from the command line.

<P>

<B>arithmetic operator</B> A symbol, such as + or /, that informs

Perl to perform arithmetic.

<P>

<B>array</B> A list of values that has been named, each of which

has a unique key for identification. The key is numeric in an

ordinary array, and a string in an associative array.

<P>

<B>array context</B> The list of values, as opposed to a single

value, returned by an expression when required by the code calling

it. It can also mean those functions that have syntax that contains

the non-terminal LIST supply array contexts of any expressions

employed as an element of the list.

<P>

<B>array literal</B> A list of scalar literals that is separated

by commas and parenthesis, but contains no variables. 

<P>

<B>array value</B> A list of scaler values with no name that can

be passed about within a script and passed to any function which

gives an array context.

<P>

<B>array variable</B> This is a named list that may be processed

by functions like splice and shift. These functions must have

an array name as their first argument.

<P>

<B>ASCII</B> American Standard Code for Information Interchange.

This is a 7-bit character code which represents 128 characters.

Some of these characters are used for communications control and

are not printable.

<P>

<B>assignment </B>A statement that is used to change the value

of a variable.

<P>

<B>assignment operator</B> An assignment statement that adapts

the value of a variable, i.e.,  $B -= 1 subtracts 1 from $B.

<P>

<B>associative array</B> Key-value pairs in a named list, which

are arranged so that any key can be used to find its associative

value.

<P>

<B>associativity</B> Deciding which operator to perform by its

precedence.

<P>

<B>autoincrement</B> To automatically add one to a value.

<P>

<B>autosplit</B> To automatically split a string or white space.

<P>

<B>awk</B> A text processing language that was a forerunner to

Perl.

<P>

<B>BLOCK</B> A structure in a Perl script that is constrained

by braces: {}.

<P>

<B>block buffering</B> Performing input and output one block at

a time, making the process more efficient.

<P>

<B>Boolean context</B> Determining truth based on one or zero;

on or off. Very handy when dealing with bits, which are either

one or zero. 

<P>

<B>browser</B> A software program that will interpret HTML documents;

a synonym for a Web client.

<P>

<B>BSD</B> Stands for Berkeley Standard Distribution.

<P>

<B>CGI</B> Common Gateway Interface. This specification, among

other things, allows browsers to communicate with external viewers,

or other applications.

<P>

<B>client</B> A software program that makes requests for information

or services from another software program called a <I>server</I>

over a network connection, like the Internet. The client then

presents this information in the manner dictated by its hardware.

<P>

<B>command</B> Any character combination in a script that causes

the Perl interpreter to take some action.

<P>

<B>compiler</B> A program that reads another program, and then

parses that script into a form that can then be executed. C is

a language that uses a compiler.

<P>

<B>data structure</B> The form various pieces of data take in

relation to each other, like a data tree.

<P>

<B>declaration</B> A message to the computer to remember something,

but not to do something. The opposite of a statement in Perl.

<P>

<B>delimiter</B> Any character or string that places a limit on

the size of any text object in Perl.

<P>

<B>DTD</B> Document Type Definition. This is a mark-up language

specification.

<P>

<B>domain name</B> An alphabetic name for a computer host. This

is the name which is mapped to the machine's numeric IP address.

<P>

<B>element</B> In Perl, the basic component of an array. In HTML,

the unit of structure in HTML documents. HTML elements each have

their own tags.

<P>

<B>environmental variable</B> A variable device that allows the

user to pass on her preferences to a script in the form of a key/value

pair, similar to an element in an associative array.

<P>

<B>EOF</B> End Of File. Used with the print command to output

designated code between EOF markers.

<P>

<B>expression</B> Anything in Perl that requires a value, like

literals, variables, operators, functions, and subroutine calls.

<P>

<B>FTP</B> File Transfer Protocol. A method of file exchange over

networks and the Internet.

<P>

<B>Gopher</B> A protocol similar to FTP. Gopher is more sophisticated,

with its use of menus that can point to files, documents, links,

or searches of other information services.

<P>

<B>global</B> A variable designation that means the entire script

can read that variable. Opposite of a local variable.

<P>

<B>hexidecimal</B> A number that is base 16. The digits 1 through

15 are represented by the letters a through f. To use hexidecimals

in Perl, prefix them with 0x.

<P>

<B>hits</B> What happens to an HTML document when it has been

accessed by a user. Useful when discussing the frequency of access

a Web site, or server, is receiving.

<P>

<B>home directory</B> The directory in which the user gains access

by their login.

<P>

<B>HTML</B> HyperText Markup Language. The language that creates

Web documents when viewed by a Web browser.

<P>

<B>HTTP</B> HyperText Tansfer Protocol. This is the protocol the

Web uses to transfer HTML documents.

<P>

<B>hypertext</B> Text that is not bound to a single flow for perception.

Web-based hypertext is not bound to a single server for creating

significance.

<P>

<B>IIS</B> Internet Information Server. The Internet service package

written by Microsoft for the NT.

<P>

<B>interpreter</B> A program that reads another program, and then

performs the tasks specified in the read script. Perl uses an

interpreter, which is different from a language like C, which

uses a compiler.

<P>

<B>ISO</B> International Standards Organization. The world-wide

organization that sets the standards for many things.

<P>

<B>Internet</B> The globally distributed collection of computers

and computer networks using the TCP/IP suite as their standard

for communication.

<P>

<B>IP</B> Stands for Internet protocol. 

<P>

<B>key</B> A piece of data that is used to find another piece

of data, the value, in an associative array.

<P>

<B>label</B> A kind of key that is linked to a statement in Perl

so it can be used elsewhere in a script.

<P>

<B>LAN</B> Local Area Network. Typically a network of computers

wired together in the same geographical location.

<P>

<B>list</B> In Perl, a set of values arranged in an ordered set.

<P>

<B>literal</B> Any number or string in a Perl script that renders

an actual value instead of a possible value.

<P>

<B>local</B> A variable designation that limits the value of that

variable to a specific, or local, area of a script.

<P>

<B>loop</B> A programming structure that allows a script to perform

an action more than once.

<P>

<B>MIME</B> Multipurpose Internet Mail Extensions. This is a specification

for multimedia documents.

<P>

<B>matrix</B> The set of computers, including large commercial

networks and the Internet, that can share e-mail through gateways.

<P>

<B>null character</B> Any character with the ASCII value of &quot;0&quot;.

<P>

<B>null list</B> Any list with the value of &quot;0&quot;.

<P>

<B>null string</B> Any string comprised of 0 characters. A string

containing a null character is not a null string, however, because

it would then contain one character. 

<P>

<B>octal</B> A number with the base of 8, running from 0 to 7.

To use an octal in Perl, use the prefix &quot;0&quot;.

<P>

<B>operator</B> A Perl function that has a special syntax or symbol.

<P>

<B>package</B> A unit in Perl code that limits access from the

other areas of the script, protecting its variables and subroutines

from being changed by another part of the script.

<P>

<B>packet</B> A unit of data used in data transmission.

<P>

<B>parsing</B> The process of turning a script into a syntax tree,

which can then be read by an interpreter and executed.

<P>

<B>path</B> The series of file names that indicates which directories

must be navigated in order to find a specific file.

<P>

<B>Perl</B> Stands for Practical Extraction and Reporting Language.

<P>

<B>pipe</B> The mechanism by which two adjacent programs are joined

within a pipeline. It is done by connecting the standard output

of one process to the standard input of another. It can also mean

the act of moving data through one of these connections.

<P>

<B>pipeline</B> An orchestration by which information is passed

from application to application in sequence.

<P>

<B>process</B> An applicaton that is currently being executed.

From UNIX.

<P>

recursion Defining something in terms of itself. 

<P>

<B>regular expressions</B> In Perl, a code line that defines a

pattern for a search to match.

<P>

<B>return value</B> The value produced when a subroutine or expression

is called in Perl. 

<P>

<B>RFC</B> Request For Comment. These are the documents that lay

down the specifications for the various technologies, protocols,

and standards used by the Internet.

<P>

<B>scalar</B> A simple value in Perl, like a number or a string.

<P>

<B>scalar literal</B> An actual quoted string or number that appears

in a Perl script. This is the opposite of a variable.

<P>

<B>SGML</B> Standard Generalized Mark-up Language. This is the

standard for defining a mark-up language, like HTML.

<P>

<B>server</B> A software application that provides services or

data in response to client requests.

<P>

<B>site</B> One or more files that deal with a self-contained

idea. They may be found on a Web, FTP, or Gopher server.

<P>

<B>slice</B> A method of selecting elements from an array.

<P>

<B>statement</B> In Perl, a command to the computer to do something

next. Opposite of a declaration.

<P>

<B>subroutine</B> A specified piece of Perl code that, once defined,

can be called into action anywhere else in the script.

<P>

<B>tags</B> The term given to the HTML codes that are used by

the Web browser to interpret the document.

<P>

<B>Telnet</B> This protocol is used to access and run a machine

from a remote location. It uses terminal emulation to share data

across a network.

<P>

<B>UNIX</B> An operating system that has variations which run

on many different types of machines.

<P>

<B>URL</B> Universal Resource Locator. This is the method for

addressing a Web file.

<P>

<B>Usenet</B> A system for distributing asynchonous text discussion

among co-operating computer hosts. Usenet is divided into newsgroups,

each specializing in a particular topic.

<P>

<B>value</B> An actual string or number.

<P>

<B>variable</B> A string or number used as a storage place in

a script for values.

<P>

<B>working directory</B> The current directory.

<P>

<B>WWW</B> Stands for World Wide Web.

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