Topic: notation for constants

topics > computer science > programming > Group: programming notation

data type by lexical constraints
data structure literals
string literals


All values, including symbolic expressions, should have a literal representation, which could be user defined. For numeric constants, the number's radix can be specified. Negative integers should have a literal representation distinct from the negation operator. Null values can be specified by contiguous commas, quote marks, or braces. A prefix to a number may indicate its data type (cbb 5/80 12/92)
Subtopic: type indicators up

Quote: prefix numbers to indicate data type; e.g. FL128 for file 128 records [»buttRA4_1975, OK]
Quote: include type indicator with literals [»cbb_1980, OK]
Quote: name qualifiers may distinguish quantities have the same type [»simoC8_1991]

Subtopic: format specification up

QuoteRef: mckeWM_1966 ;;110 number base radix-- is a string representation of a number
QuoteRef: bateF_1970 ;;174 PL/1 has literal format specification

Subtopic: null values up

QuoteRef: memorex ;;10-6 contiguous commas (operand deliminators) same as a null value

Subtopic: literal expressions up

QuoteRef: morrJH8_1972 ;;757 literal expression by french quotes eg<>
Subtopic: negative up

QuoteRef: wileDS11_1973 ;;29 has unique negative integer indicator '~'

Subtopic: history of decimal number notation up

Quote: the decimal number system appears to be of Hindu origin sometime before 595 A.D.; only India switched from the old system to the new one using the same numerical signs [»dattB_1935]
Quote: India has a place-value system of word numerals; 1 is anything markedly unique, e.g., the moon, the earth; 0 is denoted by words meaning void, sky, complete; still used today [»dattB_1935]
Quote: the earliest known use of the zero symbol is by Pingala (before 200 B.C.) [»dattB_1935]

Subtopic: history of binary number notation up

Quote: use the 5-bit teleprinter code to represent binary numbers; 0=/, 1=E, 2=@, 3=A; need to memorize [»turiA3_1951]
Quote: Turing wrote binary numbers with the low-bit first, divided into blocks of five
Quote: a large character indicates the same character repeated eight times

Related Topics up

Topic: constants (21 items)
Topic: data type by lexical constraints (15 items)
Topic: data structure literals (9 items)
Topic: string literals
(3 items)

Updated barberCB 9/04
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