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20
21<h1>Glossary</h1>
22
23<dl>
24
25<dt class="glossary"><strong>ancestor</strong><a name="ancestor"></a></dt>
26<dd>A class or parent that contributes (via inheritance) to the definition of an object. The ancestors of an object are its class and all the superclasses of its class (in class-based hierarchies) or its parent and the ancestors of its parent (in prototype-based hierarchies).</dd>
27
28<dt class="glossary"><strong>category</strong><a name="category"></a></dt>
29<dd>A set of predicates directives and clauses that can be imported by any object.</dd>
30
31<dt class="glossary"><strong>class</strong><a name="class"></a></dt>
32<dd>An object that defines the common predicates of a set of objects (its instances).</dd>
33
34<dd><dl>
35
36<dt class="glossary"><strong>abstract class</strong><a name="abstractclass"></a></dt>
37<dd>A class that cannot be instantiated. Usually used to store common predicates that are inherited by other classes.</dd>
38
39<dt class="glossary"><strong>metaclass</strong><a name="metaclass"></a></dt>
40<dd>The class of a class, when we see it as an object. Metaclass instances are themselves classes. In a reflexive system any metaclass is also an object.</dd>
41
42<dt class="glossary"><strong>subclass</strong><a name="subclass"></a></dt>
43<dd>A class that is a specialization, direct or indirectly, of another class.</dd>
44
45<dt class="glossary"><strong>superclass</strong><a name="superclass"></a></dt>
46<dd>A class from each another class is a specialization (directly or indirectly via another class).</dd>
47
48</dl></dd>
49
50<dt class="glossary"><strong>directive</strong><a name="directive"></a></dt>
51<dd>A Prolog term that affects the interpretation of Prolog code. Directives are represented using the <code>:-/1</code> prefix functor.</dd>
52
53<dd><dl>
54
55<dt class="glossary"><strong>entity directive</strong><a name="entity_directive"></a></dt>
56<dd>A directive that affects how Logtalk entities (objects, protocols, or categories) are used or compiled.</dd>
57
58<dt class="glossary"><strong>predicate directive</strong><a name="predicate_directive"></a></dt>
59<dd>A directive that affects how predicates are called or compiled.</dd>
60
61</dl></dd>
62
63<dt class="glossary"><strong>encapsulation</strong><a name="encapsulation"></a></dt>
64<dd>The hiding of an object implementation. This promotes software reuse by isolating users from implementation details.</dd>
65
66<dt class="glossary"><strong>entity</strong><a name="entity"></a></dt>
67<dd>Generic name for Logtalk compilation units: objects, categories, and protocols.</dd>
68
69<dt class="glossary"><strong>event</strong><a name="event"></a></dt>
70<dd>The sending of a message to an object. An event can be expressed as an ordered tuple: <code>(Event, Object, Message, Sender)</code>. Logtalk distinguish between the sending of a message - <code>before</code> event - and the return of control to the sender - <code>after</code> event.</dd>
71
72<dt class="glossary"><strong>grammar rule</strong><a name="grammar_rule"></a></dt>
73<dd>An alternative notation for predicates used to parse or generate sentences on some language. This notation hides the arguments used to pass the lists of tokens being processed, thus simplifying the representation of grammars. Grammar rules are represented using the infix operator <code>-->/2</code> instead of the operator used on predicate clauses (<code>:-/2</code>).</dd>
74
75<dd><dl>
76
77<dt class="glossary"><strong>grammar rule non-terminal</strong><a name="non_terminal"></a></dt>
78<dd>A syntactic category of words of phrases. A non-terminal is identified by its name and number of arguments using the notation <code>&lt;name&gt;//&lt;nargs&gt;</code>.</dd>
79
80<dt class="glossary"><strong>grammar rule terminal</strong><a name="terminal"></a></dt>
81<dd>A word or a basic symbol of a language.</dd>
82
83</dl></dd>
84
85<dt class="glossary"><strong>identity</strong><a name="identity"></a></dt>
86<dd>Property of an entity that distinguish it from every other entity. In Logtalk an entity identity can be an atom or a compound term. All Logtalk entities, objects, protocols and categories share the same name space.</dd>
87
88<dt class="glossary"><strong>inheritance</strong><a name="inheritance"></a></dt>
89<dd>An object inherits predicate directives and clauses from other objects that it extends or specializes. If an object extends other object then we have a prototype-based inheritance. If an object specializes or instantiates another object we have a class-based inheritance.</dd>
90
91<dd><dl>
92
93<dt class="glossary"><strong>private inheritance</strong><a name="private_inheritance"></a></dt>
94<dd>All public and protected predicates are inherited as private predicates.</dd>
95
96<dt class="glossary"><strong>protected inheritance</strong><a name="protected_inheritance"></a></dt>
97<dd>All public predicates are inherited as protected. No change for protected or private predicates.</dd>
98
99<dt class="glossary"><strong>public inheritance</strong><a name="public_inheritance"></a></dt>
100<dd>All inherited predicates maintain the declared scope.</dd>
101
102</dl></dd>
103
104<dt class="glossary"><strong>instance</strong><a name="instance"></a></dt>
105<dd>The same as object. This term is used when we want to emphasize that an object characteristics are defined by another object (its class).</dd>
106
107<dt class="glossary"><strong>instantiation</strong><a name="instantiation"></a></dt>
108<dd>The process of creating a new class instance.</dd>
109
110<dt class="glossary"><strong>message</strong><a name="message"></a></dt>
111<dd>A request for a service, sent to an object. In more logical terms, a message can be seen as a request for proof construction using an object's predicates.</dd>
112
113<dt class="glossary"><strong>metainterpreter</strong><a name="metainterpreter"></a></dt>
114<dd>A program capable of running other programs written in the same language.</dd>
115
116<dt class="glossary"><strong>method</strong><a name="method"></a></dt>
117<dd>Set of predicate clauses used to answer a message sent to an object. Logtalk uses dynamic binding to find which method to run to answer a message.</dd>
118
119<dt class="glossary"><strong>monitor</strong><a name="monitor"></a></dt>
120<dd>Any object that is notified when a spied event occurs. The spied events can be set by the monitor or by any other object.</dd>
121
122<dt class="glossary"><strong>object</strong><a name="object"></a></dt>
123<dd>An entity characterized by an identity and a set of predicate directives and clauses. In Logtalk objects can be either static or dynamic, like any other Prolog code.</dd>
124
125<dd><dl>
126
127<dt class="glossary"><strong>parametric object</strong><a name="parametric"></a></dt>
128<dd>An object whose name is a compound term containing free variables that can be used to parameterize the object predicates.</dd>
129
130</dl></dd>
131
132
133<dt class="glossary"><strong>parent</strong><a name="parent"></a></dt>
134<dd>An object that is extended by another object.</dd>
135
136<dt class="glossary"><strong>predicate</strong><a name="predicate"></a></dt>
137<dd>Predicates describe what is true about the application domain. A predicate is identified by its name and number of arguments using the notation <code>&lt;name&gt;/&lt;nargs&gt;</code>.</dd>
138
139<dd><dl>
140
141<dt class="glossary"><strong>local predicate</strong><a name="local_predicate"></a></dt>
142<dd>A predicate that is defined in an object (or in a category) but that is not listed in a scope directive. These predicates behave like private predicates but are invisible to the reflection methods.</dd>
143
144<dt class="glossary"><strong>metapredicate</strong><a name="metapredicate"></a></dt>
145<dd>A predicate where one of its arguments will be called as a goal. For instance, <code>findall/3</code> and <code>call/1</code> are Prolog built-ins metapredicates.</dd>
146
147<dt class="glossary"><strong>private predicate</strong><a name="private_predicate"></a></dt>
148<dd>A predicate that can only be called from the object that contains the scope directive.</dd>
149
150<dt class="glossary"><strong>protected predicate</strong><a name="protected_predicate"></a></dt>
151<dd>A predicate that can only be called from the object containing the scope directive or from an object that inherits the predicate.</dd>
152
153<dt class="glossary"><strong>public predicate</strong><a name="public_predicate"></a></dt>
154<dd>A predicate that can be called from any object.</dd>
155
156<dt class="glossary"><strong>visible predicate</strong><a name="visible_predicate"></a></dt>
157<dd>A predicate that is declared for an object, a built-in method, or a Prolog or Logtalk built-in predicate.</dd>
158
159</dl></dd>
160
161<dt class="glossary"><strong>profiler</strong><a name="profiler"></a></dt>
162<dd>A program that collects data about other program performance.</dd>
163
164<dt class="glossary"><strong>protocol</strong><a name="protocol"></a></dt>
165<dd>A set of predicates directives that can be implemented by an object or a category (or extended by another protocol).</dd>
166
167<dt class="glossary"><strong>prototype</strong><a name="protocol"></a></dt>
168<dd>A self-describing object that may extend or be extended by other objects.</dd>
169
170<dt class="glossary"><strong>self</strong><a name="self"></a></dt>
171<dd>The original object that received the message under execution.</dd>
172
173<dt class="glossary"><strong>sender</strong><a name="sender"></a></dt>
174<dd>An object that sends a message to other object.</dd>
175
176<dt class="glossary"><strong>specialization</strong><a name="specialization"></a></dt>
177<dd>A class is specialized by constructing a new class that inherit its predicates and possibly add new ones.</dd>
178
179<dt class="glossary"><strong>this</strong><a name="this"></a></dt>
180<dd>The object that contains the predicate clause under execution.</dd>
181
182</dl>
183
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189Copyright &copy; <a href="mailto:pmoura@logtalk.org">Paulo Moura</a> &mdash; <a href="http://www.logtalk.org">Logtalk.org</a>
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