By Letter: Non-alphabet | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
  Email this page to a friend

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.

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.

< Previous Terms Terms Containing pattern matching Next Terms >
pathname separator
Path Pascal
algebraic data type
Categorical Abstract Machine Language
dynamic binding
pattern recognition
PB Cache

Web Standards & Support:

Link to and support Powered by LoadedWeb Web Hosting
Valid XHTML 1.0!Valid CSS! FireFox Extensions