pattern matching
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Related to pattern matching: Pattern recognition
pattern matching
(1)A function is defined to take arguments of a particular
type, form or value. When applying the function to its actual
arguments it is necessary to match the type, form or value of
the actual arguments against the formal arguments in some
definition. For example, the function
length [] = 0 length (x:xs) = 1 + length xs
uses pattern matching in its argument to distinguish a null list from a non-null one.
There are well known algorithm for translating pattern matching into conditional expressions such as "if" or "case". E.g. the above function could be transformed to
length l = case l of [] -> 0 x:xs -> 1 : length xs
Pattern matching is usually performed in textual order though there are languages which match more specific patterns before less specific ones.
length [] = 0 length (x:xs) = 1 + length xs
uses pattern matching in its argument to distinguish a null list from a non-null one.
There are well known algorithm for translating pattern matching into conditional expressions such as "if" or "case". E.g. the above function could be transformed to
length l = case l of [] -> 0 x:xs -> 1 : length xs
Pattern matching is usually performed in textual order though there are languages which match more specific patterns before less specific ones.
pattern matching
(2)Descriptive of a type of language or utility such as awk
or Perl which is suited to searching for strings or patterns
in input data, usually using some kind of regular expression.