Th Topic: strings

Topic: strings

topics > computer science > data > Group: sequences

Topic:
boolean values, binary numbers, and bit strings
Topic:
constants
Topic:
continuation lines
Topic:
immutable files and data
Topic:
integer values and operations
Topic:
object serialization
Topic:
string literals
Topic:
string transformation languages
Topic:
string operations
Topic:
string and list concatenation
Topic:
sub-sequences
Topic:
suffix trie and suffix array
Topic:
text compression
Topic:
token
Topic:
XML data type

Summary

A string is a sequence of characters. Typically, a string is stored in memory while a file is stored on disk.
A string may have an explicit length, a maximum length, and/or a null terminator. While a null terminator is efficient, it is easily misused.
A string may be immutable. If so a string is a value. Cedar provides ropes (immutable strings) as a fundamental data type.
Strings often serve as an external data format. (cbb 7/06)

Subtopic: string as message

Quote: character strings are important for communicating between modules of a large system [»boehHJ12_1995]

Subtopic: immutable string

Quote: Cedar ropes are immutable, garbage collected, strings; same as a value [»teitW3_1985]
Quote: desired properties for strings: immutable strings, long strings, files as strings, efficient non-destructive concatenation and substring operations
Quote: represent rope/cord as an ordered concatenation tree with flat strings for leaves and shared nodes with other ropes [»boehHJ12_1995]
Quote: efficient operations on ropes/cords by storing the length of the sub-tree in each node
Quote: enhancements to ropes/cords: rebalance tree, user-defined functions at leaf nodes, substring nodes
Quote: Cedar's ropes include replacement nodes, function nodes, substring nodes, traversal by applying user-defined function to each character [»boehHJ12_1995]

Subtopic: implementation

Quote: NUL-terminated strings important for efficiency; allows fixed-length buffer that holds variable-length strings; problem of overrun [»jimT6_2002]
Quote: Multics avoids buffer overflow -- PL/I strings have a fixed maximum length; data can not be executed; virtual addresses are segmented; stacks grew up instead of down [»kargPA12_2002]
Quote: use 7- or 15-bit lengths for hashed strings; string match fails on first character [»zobeJ11_2005]

Subtopic: strings as concatenation

QuoteRef: sammJE_1969 ;;424 strings of concatenated constituents e.g., t+h+i+s. or this+is+data+.
QuoteRef: cbb_1973 ;;2/3/75 see a string constant as a string of characters not tokens.

Subtopic: problems with strings

Quote: strings are poor substitutes for value types, enumerated types, and aggregate types
[»blocJ_2001]

Related Topics

Topic: boolean values, binary numbers, and bit strings (44 items)
Topic: constants (21 items)
Topic: continuation lines (3 items)
Topic: immutable files and data (59 items)
Topic: integer values and operations (13 items)
Topic: object serialization (13 items)
Topic: string literals (3 items)
Topic: string transformation languages (17 items)
Topic: string operations (20 items)
Topic: string and list concatenation (9 items)
Topic: sub-sequences (13 items)
Topic: suffix trie and suffix array (20 items)
Topic: text compression (17 items)
Topic: token (8 items)
Topic: XML data type
(22 items)