Note: This is taken from the Chicken Wiki, where a more recent version could be available.
A generalised version of case. This case* accepts an equality predicate (the built-in case uses eqv?) and evaluates its cases instead of implicitly quoting them.
Generalised-case works like R5RS case, except that it accepts an extra argument after the key and the data in the clauses are evaluated. The special form has the name case*.
The extra argument is the equality predicate which is used to determine equality of members. The key is passed as the first parameter, the datum to match is passed as the second parameter.
<example> <init>(use generalised-case)</init> <expr> (define (foo-maker) "FOO")
(case* "foo" string-ci=?
(("bar" (foo-maker) "qux") (display "bar, foo or qux\n") 1) (else (display "We got something else\n") 2))
</expr> <result>1</result> <output>bar, foo or qux</output> </example>
Copyright (c) 2005, Peter Bex 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 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.