Topic: default value

topics > computer science > data > Group: data value

type declaration

default exception handler
initialization of data
notation for declarations
knowledge representation
programming with forms
pronoun reference
undefined, null, and other signal values


Defaults simplify the user's job by predefining his most likely choice. In parameterized type declaration, defaults provide reasonable parameters for the unknowledgeable user. As the user progresses he only needs to learn those parameters he will use. The same goes with command input and procedure calling. Format control often has defaults for the user who just wants a listing. Variables can be zeroed after use. Fill-in forms frequently contain defaults to simplify input. A good default for all user input is the user's previous input.

Program defaults, such as FORTRAN's data typing characters, can often be modified by the user; but default modification implicitly modifies the program's behavior. This is a general weakness of defaults which suggests limiting defaults to user input and unmodifiable defaults. (cbb 5/80)

Subtopic: default frame up

Quote: if a frame's slots can not be assigned according to its conditions; the network provides a replacement frame [»minsM_1981]

Subtopic: zero as default up

QuoteRef: seedH_1971 ;;67 all fields with default of zero or blank
QuoteRef: seedH_1971 ;;99 can specify fields are emptied after printing
QuoteRef: sammJE_1969 ;;452 TRAC #(cl, n, z) calls string n from current location to next segment gap. if n is empty has value of z

Subtopic: specified default up

QuoteRef: cbb_1973 ;;12/2/76 MERLIN cluster Random: MODULE seed: PAR in rationals ... seed: default-value ... then r: RANDOM (seed:123) overrides
QuoteRef: earlJ4_1974 ;;35 func ({1..m},{1..n}, real<-0) is a real n X m array with default 0

Subtopic: defaults prevail in security up

Quote: most users maintain their privacy defaults as shipped; most users think the default is correct [»paleL12_1997]

Subtopic: inheritance not good for defaults up

Quote: using IS-A links for default properties is insufficient for complex concepts and interacts badly with cancellation

Related Topics up

Group: type declaration   (5 topics, 110 quotes)

Topic: constants (21 items)
Topic: default exception handler (3 items)
Topic: initialization of data (45 items)
Topic: notation for declarations (20 items)
Topic: knowledge representation (41 items)
Topic: programming with forms (26 items)
Topic: pronoun reference (23 items)
Topic: undefined, null, and other signal values
(34 items)

Updated barberCB 5/04
Copyright © 2002-2008 by C. Bradford Barber. All rights reserved.
Thesa is a trademark of C. Bradford Barber.