Topic: value as an abstraction

topics > computer science > data > Group: data value


abstraction in programming language
enumerated data types
object and value equivalence
objects as a set of attributes
real numbers and floating point numbers
referential transparency
science as measurement
value as an object
what is a number


Values are abstractions; they have many representations and answer many questions; they exist in an ideal world. Values are not objects; their effect is only seen through use, just as the value of a cow is in one's ability to trade cows. Values are universals which differentiate possible states for use.

Computers represent values as immutable objects that are completely determined by their attributes. Typical primitive data types are immutable while data structures can be modified. Cedar defines immutable ropes and has found them useful. (cbb 5/80, 1/90)

Subtopic: value as abstraction up

Quote: an abstraction is called a value
Quote: a value, e.g., 'six feet', is an entity with many representations [»kentW_1978]
Quote: a numeral, an R-value expression, is the written representation of a number, an abstract object; only the single digits are also names [»straC8_1967]
Quote: laws of form: a bracket separates binary values [»browGS_1972]
Quote: lengths, colors etc. can occur in a database without existence being announced [»kentW1_1984]
Quote: real numbers are unrepresentable ideals which are approximated in a computer [»wegnP10_1986, OK]
Quote: use "all ..." for queries; returns all cards with that value in any property; ignores trailing "s" [»paneJF9_2002]

Subtopic: value as number up

QuoteRef: cbb_1973 ;;8/18/74 the value of a cow is not the cow but in some logical units ... value is in terms of some set of literals
Quote: every number is the answer to squillons of questions [»fynn_1974]

Subtopic: value as referentially transparent up

Quote: values are referentially transparent while objects are referentially opaque; i.e., values do not have side effects and identical values may be substituted freely [»taivA4_1993]
Quote: no value shall possess an ID that is distinct from the value per se [»dateCJ_1998]
Quote: referential transparency means that the value of an expression is determined by the values of its sub-expressions [»straC8_1967]

Subtopic: value depends on syntax up

Quote: the symbol string 1+5 is not 6 in all circumstances, for example 21+52; requires syntactic analysis

Subtopic: value as immutable up

Quote: objects and variables retain their identity during change but values can never change [»maclBJ12_1982]
Quote: Cedar ropes are immutable, garbage collected, strings; same as a value [»teitW3_1985]
Quote: an abstraction is completely defined by its attributes; it can't be modified [»maclBJ12_1983]
Quote: laws of form: value of a mark is the value of the surrounding space [»browGS_1972]
Quote: laws of form: repeated calls have the same value [»browGS_1972]

Subtopic: value as atomic, internal relation up

Quote: a value is completely determined by its internal relations and properties
Quote: uniqueness of an object depends only on its external relations; exactly the opposite of a value [»maclBJ12_1982]
Quote: programming languages treat atomic data types as values and compound ones as objects; causes unnecessary confusion [»maclBJ12_1982]
Quote: abstractions either have an "eternal" existence (values, concepts) or a temporary, tangible existence (objects) [»taivA4_1993]

Subtopic: values as objects up

Quote: computers must represent values as objects since abstractions are not physical [»maclBJ12_1982]
Quote: the state, or value, of an object is the value of its members and the objects it references [»stroB_1991]
Note: a parameter is an object field, a reference to a pointer; value semantics is an optimization
[»cbb_1990, OK]

Related Topics up

Group: philosophy   (60 topics, 2323 quotes)

Topic: abstraction in programming language (47 items)
Topic: constants (21 items)
Topic: enumerated data types (17 items)
Topic: object and value equivalence (60 items)
Topic: objects as a set of attributes (39 items)
Topic: real numbers and floating point numbers (37 items)
Topic: referential transparency (26 items)
Topic: science as measurement (36 items)
Topic: value as an object (29 items)
Topic: what is a number
(55 items)

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