I've a better idea. Establish a new system flag called (say) VERSION_z_ and assign it within stdlib.ijs (c/f IFJHS or JLIB) the integer form of the J version (currently this would be VERSION_z_ = 951).
Then ~addons/math/cal/cal.ijs, or some other utility with a version dependency, could test for J version being higher than 9.0.0 (say) like this: if. VERSION>900 do. ... If VERSION_z_ is undefined, then instead of the current opaque error message: load 'math/cal' |ill-formed number: script | 9.5.1 | ^ | 900< ".}.'/'taketo 9!:14'' |[-32] /applications/j9.5/addons/math/cal/cal.ijs the addon will fail with: load 'math/cal' |value error: VERSION | VERSION>900 |[-32] /applications/j9.5/addons/math/cal/cal.ijs The fix will be obvious to someone with only weak J skills. Thus the user might insert this line into ~config/startup.ijs: VERSION_z_ =: 951 On Fri, 22 Dec 2023 at 04:48, Raul Miller <rauldmil...@gmail.com> wrote: > Hmm... only if we're updating stdlib, supporting versions of J back to > 4.0.1. A worthwhile effort, though, if someone was actually tackling > those issues. > > Otherwise, I think an idiom would be about as good as it gets. > > -- > Raul > > > On Thu, Dec 21, 2023 at 9:24 PM Ian Clark <earthspo...@gmail.com> wrote: > > > > For those of us digital archaeologists running back-levels of J, it would > > be nice to have a robust test for a given version of J or later which > > tolerates versions down to 4.01, say. > > > > > > What represents best-practice? The best I can come up with is: > > > > jversion=: 3 : 0 > > > > ". 'j.' -.~ '/' taketo 9!:14'' > > > > ) > > > > > > > > which reliably returns a 3-digit integer, permitting (say): > > > > if. 900 <: jversion'' do. … > > > > > > A candidate for stdlib? > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
