s=: 1 $. 100;0;2 t=: 1 $. 200;0;3 s,"0/t |non-unique sparse elements | s ,"0/t
For that matter, I'd expected that s,t would signal the same error, but it doesn't. I guess if I looked at the source I can figure out why that is. s,t |nonce error | s ,t In contrast: s ,"0/ s $ s ,"0/ s 100 100 2 3 $. s ,"0/ s NB. the sparse element 2 I expect "read only data" to be signaled if you try to amend data which is mapped on a read-only file (e.g. if the mapped file is on a CDROM). "stop" would be signaled when execution reaches a line in an explicit defn which has stop set. "break" would be signaled if (on Windows) you hit the yellow J icon while the J session is executing. e.g. execute 6!:3]100 and then hit the yellow icon 2 or 3 times. "input interrupt" would be signaled if you asked for "terminal input", 1!:1]1, hit the yellow icon, and then enter. It dates from a time when it was possible to enter o backspace u backspace t (remember that?) in response to 1!:1]1. "system error" is not supposed to happen. Not sure about "file access error". On Tue, May 20, 2014 at 2:32 PM, Ian Clark <[email protected]> wrote: > For NuVoc purposes I'm documenting J's error messages... > > Have you ever seen any of the following error messages in your J session > (j602 onwards)? > > allocation error > break > file access error > input interrupt > non-unique sparse elements > read-only data > stop > system error > > If so, can you furnish a simple sample of "normal" J code that causes the > said error? > > I specify "normal" because I don't want samples which rely on constructing > a pathological noun as a core image in hex and shoe-horning it into J by > use of 3!:2, or use of the "darker" Foreigns, especially undocumented ones. > I want something which could conceivable arise by bona-fide J usage by an > innocent newbie, ill-conceived though it might seem to someone more > experienced. > > Having said that, it probably takes deep knowledge of the J source to know > what might trigger some of these errors. > > It would also be nice to know which of the above error messages can't > possibly arise in normal usage. (But consider it "cheating" to use 13!:8 to > signal any given message: assume I know how to do that.) > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
