i have no idea, at the opposite, in one of my program i experienced a vector implementation faster than the list one.
Regards, Damien On Wed, Dec 28, 2022 at 2:23 PM Sascha Ziemann <cev...@gmail.com> wrote: > I spent my Christmas vacation playing with XML and tree traversal. And > I have observed some strange timings, while measuring the execution > time of different algorithms. My test file is the XCB XML schema: > > https://cgit.freedesktop.org/xcb/proto/plain/src/xcb.xsd > > And my test program is this: > > https://gist.github.com/ceving/6eb3792c64e505909f43858039ae18f8 > > I load the XSD file with "(sxml simple)" and traverse the XML tree in > order to remove all white-spaces. During the traversal of the tree I > visit each element and destructure each element with the following > procedure: > > (define (sxml:call-with-element node proc) > (if (sxml:element? node) > (let ((name (car node)) > (rest (cdr node))) > (if (pair? rest) > (let ((maybe-attributes (car rest))) > (if (sxml:attributes? maybe-attributes) > (proc name (cdr maybe-attributes) (cdr rest)) > (proc name '() rest))) > (proc name '() '()))) > node)) > > This is necessary, because in SXML the first child of an element may > be an attribute list of an actual child element. After I had written > the procedure, I had the impression that it might be faster to work > with vectors instead of lists, because the version with vectors looks > much simpler: > > (define (vxml:call-with-element node proc) > (if (vxml:element? node) > (proc (vxml:element-name node) > (vxml:element-attributes node) > (vxml:element-children node)) > node)) > > But after I compared the two traversals, I had to realize that the > list-version is a bit faster than the vector-version. Although the > list-version does much testing, caring and cdring, the straight > forward vector-ref's are slower. Can anybody explain? > >
