Topic: pattern components

topics > computer science > programming > Group: patterns

pattern matching
pattern specification


The classes within a pattern specification define sub-sequences and location indices which can be assigned to variables. Similarly leading and trailing sub-sequences can be assigned. Pattern component variables may be involved in the matching process, two pattern matches may define a subsequence between them. Once matching is completed, the pattern determines a structure with a pattern component variables as the components of that structure. (cbb 5/80)
Subtopic: pattern variables up

QuoteRef: farbDJ1_1964 ;;24 all scans left to right so use pattern variables as pattern literals in the same search
QuoteRef: grisRE_1972 ;;30 on match, matched pattern to word eg text arb.word (arb any chars)
QuoteRef: sammJE_1969 ;;456 in pattern specification same name refers to same element in class
QuoteRef: memorex ;;2-10 variable symbols (eg &abc) are replaced by string form of value
Quote: Vulcan defines infix operator x/a.y.c where a. and .c receive pre and post context [»storEF_1970, OK]

Subtopic: predefined variables up

QuoteRef: grisRE_1972 ;;31 within a pattern $word is replaced with each partial match

Subtopic: positional variable up

QuoteRef: grisRE_1972 ;;31 @var matches null string, returns position within the string
QuoteRef: sammJE_1969 ;;428 numeric subscripts in pattern specification-- equals (.n), equals subscript of another constitute (.*j), greater than (.Gn or.G.*j , less than, and none (-.) eg c/.g25,.l35 tests the numeric range

Subtopic: binding time up

QuoteRef: grisRE_1972 ;;34 when specifying a variable can use *variable to indicate don't evaluate until execute pattern search

Subtopic: pattern operators up

Quote: Icon has scanning operations for upto©, many©, any©, find(s), match(s), &, | [»grisRE4_1980]
Quote: the 'upto(...)' operation in Icon, scans until the first occurrence of a letter [»grisRE4_1980]
Quote: the Icon scanning operation, upto©, is a generator that returns values until the expression succeeds [»grisRE4_1980]

Subtopic: context matching up

Quote: Vulcan defines infix operator x/a.y.c where a. and .c receive pre and post context [»storEF_1970, OK]
Quote: Imp uses contextual string resolution; so p->q.(s).r picks and left and right context of s [»stepPD8_1974, OK]

Subtopic: synonymns and noise words up

Quote: TUTOR includes lists of synonymous words and lists of noise words to simplify analysis of student responses

Related Topics up

Group: parameters   (10 topics, 145 quotes)
Topic: pattern matching (42 items)
Topic: pattern specification
(15 items)

Updated barberCB 10/04
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