1. {application program}.

	2. {function application}.

<standard, programming> (CORBA) An {Object Management Group}
	specification which provides a standard messaging interface
	between distributed {objects}.

	The original CORBA specification (1.1) has been revised
	through version 2 (CORBA 2) with the latest specification
	being version 3 (CORBA 3).  In its most basic form CORBA
	consists of the {Interface Definition Language} (IDL) and the
	Dynamic Invocation Interface (DII).

	The IDL definition is complied into a Stub (client) and
	Skeleton (server) component that communicate through an
	{Object Request Broker} (ORB).  When an ORB determines that a
	request is to a remote object, it may execute the request by
	communicating with the remote ORB.

	The Corba IDL can be mapped to a number of languages including
	{C}, {C++}, {Java}, {COBOL}, {Smalltalk}, {Ada}, {Lisp},
	{Python}, and {IDLscript}.  CORBA ORBs are widely available
	for a number of platforms.  The OMG standard for inter-ORB
	communication is {IIOP}, this ensures that all CORBA 2
	compliant ORBS are able to interoperate.

	See also {COSS}, {Component Object Model}, {RMI}.

	{OMG CORBA site (http://www.corba.org/)}.

	(2003-11-21)

Basic programming Environment for interactive-graphical
	Applications, from Siemens-Nixdorf.

<programming> A special value used in several languages to
	represent the thing referred to by an uninitialised pointer.

	<database> A special value that may be stored in some database
	columns to represent an unknown, missing, not applicable, or
	undefined value.  Nulls are treated completely differently
	from ordinary values when evaluating SQL expressions and there
	are several SQL constructs for dealing with nulls.

	(2003-06-17)

(Historically, "according to religious law")

	1. <mathematics> A standard way of writing a formula.  Two
	formulas such as 9 + x and x + 9 are said to be equivalent
	because they mean the same thing, but the second one is in
	"canonical form" because it is written in the usual way, with
	the highest power of x first.  Usually there are fixed rules
	you can use to decide whether something is in canonical form.
	Things in canonical form are easier to compare.

	2. <jargon> The usual or standard state or manner of
	something.  The term acquired this meaning in computer-science
	culture largely through its prominence in {Alonzo Church}'s
	work in computation theory and {mathematical logic} (see
	{Knights of the Lambda-Calculus}).

	Compare {vanilla}.

	This word has an interesting history.  Non-technical academics
	do not use the adjective "canonical" in any of the senses
	defined above with any regularity; they do however use the
	nouns "canon" and "canonicity" (not "canonicalness"* or
	"canonicality"*). The "canon" of a given author is the
	complete body of authentic works by that author (this usage is
	familiar to Sherlock Holmes fans as well as to literary
	scholars).  "The canon" is the body of works in a given field
	(e.g. works of literature, or of art, or of music) deemed
	worthwhile for students to study and for scholars to
	investigate.

	The word "canon" derives ultimately from the Greek "kanon"
	(akin to the English "cane") referring to a reed.  Reeds were
	used for measurement, and in Latin and later Greek the word
	"canon" meant a rule or a standard.  The establishment of a
	canon of scriptures within Christianity was meant to define a
	standard or a rule for the religion.  The above non-technical
	academic usages stem from this instance of a defined and
	accepted body of work.  Alongside this usage was the
	promulgation of "canons" ("rules") for the government of the
	Catholic Church.  The usages relating to religious law derive
	from this use of the Latin "canon".  It may also be related to
	arabic "qanun" (law).

	Hackers invest this term with a playfulness that makes an
	ironic contrast with its historical meaning.  A true story:
	One Bob Sjoberg, new at the {MIT AI Lab}, expressed some
	annoyance at the incessant use of jargon.  Over his loud
	objections, {GLS} and {RMS} made a point of using as much of
	it as possible in his presence, and eventually it began to
	sink in.  Finally, in one conversation, he used the word
	"canonical" in jargon-like fashion without thinking.  Steele:
	"Aha!  We've finally got you talking jargon too!"  Stallman:
	"What did he say?"  Steele: "Bob just used "canonical" in the
	canonical way."

	Of course, canonicality depends on context, but it is
	implicitly defined as the way *hackers* normally expect things
	to be.  Thus, a hacker may claim with a straight face that
	"according to religious law" is *not* the canonical meaning of
	"canonical".

	(2002-02-06)

<programming> A constant made available to a process, by
	inclusion in the executable text.  Most modern systems do not
	allow texts to modify themselves during execution, so literals
	are indeed constant; their value is written at compile-time
	and is read-only at run time.

	In contrast, values placed in variables or files and accessed
	by the process via a symbolic name, can be changed during
	execution.  This may be an asset.  For example, messages can
	be given in a choice of languages by placing the translation
	in a file.

	Literals are used when such modification is not desired.  The
	name of the file mentioned above (not its content), or a
	physical constant such as 3.14159, might be coded as a
	literal.  Literals can be accessed quickly, a potential
	advantage of their use.

	(1996-01-23)

/nil/ 1. New Implementation of Lisp.  A language intended to
	be the successor of {MacLisp}.  A large {Lisp}, implemented
	mostly in {VAX} {assembly language}.  A forerunner of {Common
	LISP}.

	["NIL: A Perspective", Jon L. White, MACSYMA Users' Conf Proc,
	1979].

	2. Network Implementation Language.  Strom & Yemini, TJWRC,
	IBM.  Implementation of complex networking protocols in a
	modular fashion.

	["NIL: An Integrated Language and System for Distributed
	Programming", R. Strom et al, SIGPLAN Notices 18(6):73-82
	(June 1983)].

	3. Empty list or False.  In {Lisp}, the empty list (or "nil
	list") is used to represent the {Boolean} value False.  This
	is possible because {Lisp} is not typed.  True is represented
	by the special {atom} "t".

	4. Spoken in reply to a question, particularly one asked using
	the "-P" convention it means "No".  Most hackers assume this
	derives simply from LISP, but NIL meaning "no" was
	well-established among radio hams decades before LISP existed.
	The historical connection between early hackerdom and the ham
	radio world was strong enough that this may have been an
	influence.

	[{Jargon File}]

<software> Instructions for a computer in some programming
	language, often {machine language}.  The word "code" is often
	used to distinguish instructions from {data} (e.g. "The code
	is marked 'read-only'") whereas "{software}" is used in
	contrast with "{hardware}" and may consist of more than just
	code.

	(2000-04-08)

<storage, architecture, jargon, theory> How something is; its
	configuration, attributes, condition, or information content.
	The state of a system is usually temporary (i.e. it changes
	with time) and volatile (i.e. it will be lost or reset to some
	initial state if the system is switched off).

	A state may be considered to be a point in some {space} of all
	possible states.  A simple example is a light, which is either
	on or off.  A complex example is the electrical activation in
	a human brain while solving a problem.

	In computing and related fields, states, as in the light
	example, are often modelled as being {discrete} (rather than
	continuous) and the transition from one state to another is
	considered to be instantaneous.  Another (related) property of
	a system is the number of possible states it may exhibit.
	This may be finite or infinite.  A common model for a system
	with a finite number of discrete state is a {finite state
	machine}.

	[{Jargon File}]

	(1996-10-13)