This extension provides a procedure (slice) for slicing lists, vectors and strings. Slicing is quite flexible: negative indexes may be used for either the from index or for the to index.
Since version 1.1, UTF-8 is supported (use the slice-utf8 module).
Procedures[procedure] (slice object #!optional from to)
Slice the given object returning the slice from from to to.
If to is ommited and from is positive, return the slice from from to the last element of the given object.
If to is ommited and from is negative, return the slice from from, assuming from is the counted from the end of object, to the last element of the given object.
(define v '#(1 2 3 4 5 6 7)) (slice v 0 0) => #() (slice v 1 0)) => #() (slice v 0 1)) => #(1) (slice v 1 3)) => #(2 3) (slice v 10 10)) => #() (slice v 0 10)) => #(1 2 3 4 5 6 7) (slice v 10 0)) => #() (slice v 0)) => #(1 2 3 4 5 6 7) (slice v -1)) => #(7) (slice v 10)) => #() (slice v -10)) => #(1 2 3 4 5 6 7) (slice v -4)) => #(4 5 6 7) (slice v -4 -4)) => #() (slice v -4 -2)) => #(4 5) (slice v -4 -10)) => #() (slice v -10 -4)) => #(1 2 3)
If from and to are ommited, the object argument is expected to be a procedure to be added to the set of slicers known by slice. The given procedure is an one-argument one which should check for the type of the object it is given and return a slicer procedure, which should accept an object, the from and to indexes.
(define s (make-custom-string "custom string")) (slice (lambda (obj) (and (custom-string? obj) (lambda (obj from to) (handle-exceptions exn "" (substring (custom-string-text obj) from to)))))) (slice s 0 1) => "c"
Copyright (c) 2010-2014, Mario Domenech Goulart All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. 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. 3. The name of the authors may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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.
- Assume numbers internally are fixnums
- Fix cases like (slice "1234567" 2 -2)
- UTF-8 support (slice-utf8 module)
- Compiled with -O3
- Initial release