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QuoteRef: handP_1981
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ThesaHelp:
references g-h
Topic:
design languages
Topic:
programming with natural language
Group:
requirement specification
Topic:
mental models, consistency, and interface metaphors
Topic:
software models of reality
Topic:
program source as truth
Topic:
database entities
Topic:
attribute-value pairs as information
Topic:
graphs
Group:
variables
Topic:
primitive data types for Thesa
Topic:
Thesa data model
Topic:
database as a model of reality
Topic:
data type as a set of values and a set of operations
Topic:
science as measurement
Topic:
safe use of pointers
Topic:
pointers to data
Topic:
classification
Topic:
data type as a set of variables
Topic:
function vs. procedure
Topic:
type hierarchy
Topic:
event time
Topic:
primitive functions
Topic:
function call
Topic:
production systems
Topic:
events
Topic:
event controlled processing
Topic:
concurrency
Topic:
interrupts
Topic:
high priority processes
Reference
Handlykken, P. , Nygaard, K. , "The DELTA system description language: Motivation, main concepts and experience from use", in Hunke H. (ed.), Software Engineering environments , North-Holland, pp. 173-190, 1981. Google
174 ;;Quote: DELTA language is for communication between analysts and users, analysts and trade unions, programmers and scientists
174 ;;Quote: should be able to describe systems naturally; requires description of alternate views
174 ;;Quote: formal and natural language descriptions of a system should fit well together
175 ;;Quote: we need an external model to portray the properties of a complex system; the model itself is a system
176 ;;Quote: a computer program is a prescription for computer behavior
177 ;;Quote: DELTA is made of objects represented by entities; entities are the nodes of a directed graph
177 ;;Quote: attributes of an object are annotations to the nodes of the directed graph representing the system
178 ;;Quote: a quantity is a name with a type and a value
178 ;;Quote: quantities in the model system usually corresponds to a property of a component of the referent system
178 ;;Quote: a data type indicates how something is measured, its set of possible values, and its set of possible operations
178 ;;Quote: a reference consists of a descriptive name, a target set (its qualification), and a target (its value or NONE)
178 ;;Quote: categories are defined by patterns; includes data types, classes, procedures, and functions
178+;;Quote: a procedure is a rule for the execution of actions
178+;;Quote: a function is a rule for defining a value of a given type; either quantity or reference
179 ;;Quote: in DELTA, an object's sequential actions are specified by a prime task which is a separate entity
179 ;;Quote: DELTA defines a hierarchy of objects; objects can not exist without their parent existing
180 ;;Quote: a class of objects is defined by a pattern giving a set of attributes and a set of actions
180 ;;Quote: in DELTA time is defined by a global variable; next version of DELTA will use a petri net definition of time
181 ;;Quote: a DELTA action is either a procedure call (partial task) or a basic action defined by the language
181 ;;Quote: a DELTA procedure is a partial task, connected to the prime task or partial task; discarded when finished
181 ;;Quote: DELTA's main loop: determine effective descriptors with true conditions, find a satisfying assignment for variables modified by the descriptor's actions
182 ;;Quote: DELTA events occur when an action's condition no longer holds; proceeds to next action in the object's sequence
182 ;;Quote: simultaneous, independent events execute in an unpredictable order
182 ;;Quote: a DELTA event sends an interrupt to an object by appending a task pattern to the object's agenda; executed if higher priority
ThesaHelp: references g-h (299 items)
Topic: design languages (12 items)
Topic: programming with natural language (27 items)
Group: requirement specification (11 topics, 306 quotes)
Topic: mental models, consistency, and interface metaphors (49 items)
Topic: software models of reality (22 items)
Topic: program source as truth (17 items)
Topic: database entities (12 items)
Topic: attribute-value pairs as information (53 items)
Topic: graphs (18 items)
Group: variables (10 topics, 128 quotes)
Topic: primitive data types for Thesa (82 items)
Topic: Thesa data model (58 items)
Topic: database as a model of reality (25 items)
Topic: data type as a set of values and a set of operations (16 items)
Topic: science as measurement (36 items)
Topic: safe use of pointers (102 items)
Topic: pointers to data (55 items)
Topic: classification (64 items)
Topic: data type as a set of variables (11 items)
Topic: function vs. procedure (9 items)
Topic: type hierarchy (18 items)
Topic: event time (44 items)
Topic: primitive functions (34 items)
Topic: function call (28 items)
Topic: production systems (10 items)
Topic: events (44 items)
Topic: event controlled processing (46 items)
Topic: concurrency (33 items)
Topic: interrupts (25 items)
Topic: high priority processes (13 items)