chickadee » regex-case

regex-case

Description

An easy to use case construct for matching regular expressions.

Author

felix winkelmann

Requirements

None

Documentation

(regex-case EXPRESSION CLAUSE ...) syntax

Evaluates EXPRESSION and executes the body of the first CLAUSE that matches. Each CLAUSE should be of the form:

 (REGEX LAMBDA-LIST BODY ...)

The variables in LAMBDA-LIST are bound to the results of evaluating the expression

 (string-match REGEX STRING)

The last CLAUSE may also be

 (else BODY ...)

If no CLAUSE matches, the form returns an undefined result.

Examples

(use regex-case)

(define (test x)
  (regex-case x
    ["[a-z]+" _ 'word]
    ["[0-9]+" _ 'num]
    [else 'nothing] ) )

(test "42")
 => 'num

(test "hello")
 => 'word

(test "???")
 => 'nothing
(use regex-case)

(regex-case "one23four"
  ["[a-z]+([0-9]+).*" (all num) num] )
 => "23"
(use regex-case)

(regex-case "http:www.foo.com/index.html" 
  ["([a-z]+):([a-z0-9.-]+)(/(.*))?" (_ . parts) parts])
 =>
("http" "www.foo.com" "/index.html" "index.html")

Changelog

License

 Copyright (c) 2003, Felix L. Winkelmann
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
 conditions are met:
 
   Redistributions of source code must retain the above copyright notice, this list of conditions and the following
     disclaimer. 
   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
     disclaimer in the documentation and/or other materials provided with the distribution. 
   Neither the name of the author nor the names of its contributors may be used to endorse or promote
     products derived from this software without specific prior written permission. 
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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