mbolivar - <>If you have an implementation you'd like included in libmaple, I'm sure we'd be grateful. </>
I found the book we used for Shell sort. It was dark red, and not green, which slowed me down a lot :-)
It was "Handbook of Algorithms and Data Structures in Pascal and C" by G H Gonnet, ISBN 0-201-14218-X Copyright 1984. My copy has a note before the preface to say the code is available on 9 track tape, 1600bpi, for US$95. So not a good candidate for Maplelib.
Th=at book has been superceeded by the 1991 edition
For the 1991 book there is a web site http://www.dcc.uchile.cl/~rbaeza/handbook/hbook.html
with the source code.
So the Shell sort is at http://www.dcc.uchile.cl/~rbaeza/handbook/algs/4/414.sort.c.html
I think we futzed with the step values, maybe from Knuth.
Anyway, I have't found the license on that code, but it may be a suitable starting place for maplelib.