1. <programming> {fill-out form}.

	2. <library> (Xforms) A {GUI} component library for {X11}.

	(1998-03-24)

1. <programming> The prototype for an {object} in an
	{object-oriented language}; analogous to a {derived type} in a
	{procedural language}.  A class may also be considered to be a
	set of objects which share a common structure and behaviour.
	The structure of a class is determined by the {class
	variables} which represent the {state} of an object of that
	class and the behaviour is given by a set of {methods}
	associated with the class.

	Classes are related in a {class hierarchy}.  One class may be
	a specialisation (a "{subclass}") of another (one of its
	"{superclasses}") or it may be composed of other classes or it
	may use other classes in a {client-server} relationship.  A
	class may be an {abstract class} or a {concrete class}.

	See also {signature}.

	2. <programming> See {type class}.

	3. <networking> One of three types of {Internet addresses}
	distinguished by their most significant bits.

	3. <language> A language developed by the {Andrew Project}.
	It was one of the first attempts to add {object-oriented}
	features to {C}.

	(1995-05-01)

1. <hardware> the maximum number of {pixels} that can be
	displayed on a {monitor}, expressed as (number of horizontal
	pixels) x (number of vertical pixels), i.e., 1024x768.  The
	ratio of horizontal to vertical resolution is usually 4:3, the
	same as that of conventional television sets.

	2. <logic> A mechanical method for proving statements of
	{first order logic}, introduced by J. A. Robinson in 1965.
	Resolution is applied to two {clauses} in a {sentence}.  It
	eliminates, by {unification}, a {literal} that occurs
	"positive" in one and "negative" in the other to produce a new
	clause, the {resolvent}.

	For example, given the sentence:

		(man(X) => mortal(X))  AND  man(socrates).

	The literal "man(X)" is "negative".  The literal
	"man(socrates)" could be considered to be on the right hand
	side of the degenerate implication

		True => man(socrates)

	and is therefore "positive".  The two literals can be unified
	by the binding X = socrates.

	The {truth table} for the implication function is

		A | B | A => B
		--+---+-------
		F | F |   T
		F | T |   T
		T | F |   F
		T | T |   T

	(The implication only fails if its premise is true but its
	conclusion is false).  From this we can see that

		A => B   ==   (NOT A) OR B

	Which is why the left hand side of the implication is said to
	be negative and the right positive.  The sentence above could
	thus be written

		((NOT man(socrates)) OR mortal(socrates))
		AND
		man(socrates)

	Distributing the AND over the OR gives

		((NOT man(socrates)) AND man(socrates))
		OR
		mortal(socrates) AND man(socrates)

	And since (NOT A) AND A == False, and False OR A == A we can
	simplify to just

		mortal(socrates) AND man(socrates)

	So we have proved the new literal, mortal(socrates).

	Resolution with {backtracking} is the basic control mechanism
	of {Prolog}.

	See also {modus ponens}, {SLD Resolution}.

	3. <networking> {address resolution}.

	(1996-02-09)

<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)

1. A discrepancy between a computed, observed, or measured
	value or condition and the true, specified, or theoretically
	correct value or condition.

	2. <programming> A mental mistake made by a programmer that
	may result in a program {fault}.

	3. (verb) What a program does when it stops as result of a
	programming error.

	(2000-03-28)

1. <tool> A program used primarily to create, manipulate,
	modify, or analyse other programs, such as a compiler or an
	editor or a cross-referencing program.  Opposite: {app},
	{operating system}.

	2. A {Unix} {application program} with a simple, "transparent"
	(typically text-stream) interface designed specifically to be
	used in programmed combination with other tools (see {filter},
	{plumbing}).

	3. <jargon> ({MIT}: general to students there) To work; to
	study (connotes tedium).  The {TMRC} Dictionary defined this
	as "to set one's brain to the grindstone".  See {hack}.

	4. <jargon, person> ({MIT}) A student who studies too much and
	hacks too little.  MIT's student humour magazine rejoices in
	the name "Tool and Die".

	[{Jargon File}]

	(1996-12-12)