Topic: data type by lexical constraints

topics > computer science > data > Group: data type

programming notation
data type as a set of values
data type by name or tags
declaration through use
lexical analysis
naming conventions
notation for constants
notation for declarations
XML data type


The name of a reference can declare its type. For instance in Fortran an initial letter "I" indicates an integer variable. This practice is no longer used. (cbb 5/80)

Lexical typing works for numeric constants. It is also good for indicating the kind of object, e.g., classes vs. variables vs. operation (cbb 1/90)

Lexical conventions may indicate the location or namespace of a name. For example 'm_' may be used to indicate properties of a class. (cbb 5/06)

Subtopic: type by syntax up

Quote: syntactic checks for existence: a symbol is numeric, alphabetic, fixed length [»kentW_1978]
Quote: syntactic test of existence works for numbers, but not for strings, e.g., addresses [»kentW_1978]
Quote: a symbol type is the lexical constraints on allowable strings [»kentW1_1984]
Quote: a entity type has a name, super type or symbol type [»kentW1_1984]
Quote: define a domain as a syntactic pattern, e.g., names are first_name, last_name [»mcleDJ3_1976, OK]
Quote: Proteus included the format of literals as part of a type definition [»solnN_1971, OK]
Quote: the syntax of a literal defines a calculation that converts a print name into an internal value [»wulfWA4_1974]
Quote: Smalltalk classes start with uppercase while variables are lowercase [»xlrg8_1981]
Quote: each variable has a prefix to identify data type and scalar vs. aggregate [»browRE7_1976]
Quote: include type indicator with literals [»cbb_1980, OK]

Subtopic: type prefix up

Quote: for type tags use two or three characters; may be random, must correspond to types [»simoC8_1991]
Quote: prefix numbers to indicate data type; e.g. FL128 for file 128 records [»buttRA4_1975, OK]
QuoteRef: bennRK6_1968 ;;3-8 allows symbol prefixes to indicate default type (eg fortran's i2)
QuoteRef: bennRK6_1968 ;;3-3 splits words into semantic types eg subroutine, infix operator, list. These can be changed
QuoteRef: wileDS11_1973 ;;29 basic types (indicated by letter) signed integer, character, sequence, empty (nil) and string (sequence of characters)

Related Topics up

Group: programming notation   (14 topics, 221 quotes)
Topic: constants (21 items)
Topic: data type as a set of values (20 items)
Topic: data type by name or tags (29 items)
Topic: declaration through use (7 items)
Topic: lexical analysis (14 items)
Topic: naming conventions (8 items)
Topic: notation for constants (14 items)
Topic: notation for declarations (20 items)
Topic: XML data type
(22 items)

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