> _J for C Programmers_ (http://www.jsoftware.com/help/jforc/contents.htm)

Thanks. For those who prefer PDFs, that book and more material are available at http://www.jsoftware.com/jwiki/Books . (Had to dig around a bit, because, in spite of the original URL, the book was not listed in the help page.)

Question: I have a vague memory of seeing a web page named something like "A Garden of ..." with neat examples, either for J or K. However, my search-fu is failing me.

Something like http://www.jsoftware.com/jwiki/Essays ?

Yes, that's probably it, thank you. (There's a couple of brain cells in the back muttering that the page was less dense and tan colored, but I told them to shut up ;-)

Now let's sell tickets to some cage fights, for instance http://www.jsoftware.com/jwiki/Essays/Sudoku versus http://norvig.com/sudoku.html

P.S. The credit at the bottom of the J Sudoku piece led me here: http://www.vector.org.uk/ . Seems an interesting place to visit. It even features articles headed "APL is not for programmers" (quote: "At this point the average programmer turns off, drops out, gets his coat and leaves the building, heading for mom and the kids. We, on the other hand, will continue.")

If you want cage fights, you should also include the lean contender: http://nsl.com/k/sudoku/aw3.k

(I'll copy it here, because it's short enough for that:

  p,:3/:_(p:9\:!81)%3
  s:{*(,x)(,/{@[x;y;:;]'&21=x[&|/p[;y]=p]?!10}')/&~x}

Very cool, I should look into this. IBM APL2 was one of the first languages I spewed out lots of code in (the others being awk, C, scheme and some proprietary database langauges, ). The APL workspaces I worked on were some of the largest in existence, according to IBM consultants we had on-site (tens of thousands of lines of code, if I remember correctly). Whew.

Thanks. I'm glad you keep on top of this stuff for us. Interesting to see the name Iverson in the OP; is Eric Ken's son?

I believe so, yes.

I glanced over the J for C table of contents to find out where J keeps anything like product and sum types, but I found no promising headlines. Is that just J's way of saying "if it's not a matrix, don't use J", or am I missing something fundamental here?

Box/open are the primitives you want. Box wraps other values (possibly with different types or sizes) in one array, kind of like a C struct. Open extracts sub-elements.

Box: http://www.jsoftware.com/help/dictionary/d010.htm

Open: http://www.jsoftware.com/help/dictionary/d020.htm