> And, most of us lapse into JTRAN occasionally. (maybe not Roger) https://code.jsoftware.com/wiki/Essays/Knight%27s_Tour Well, the code is not scalar JTRAN but is loopy.
On Sat, Aug 28, 2021 at 9:02 PM Henry Rich <[email protected]> wrote: > Thanks for the reference. By my analysis, the beta-o parser would not > be any faster than it is if it had to verify the types of its arguments. > > Your last point is absolutely right, and yet I want to ignore it. > Experienced J programmers have learned ways to avoid sentences that do > little work. Programmers new to J write what I call JTRAN: FORTRAN code > translated to J, with lots of scalar arithmetic. With a little > experience they will write better J, but I don't want to lose them > before they get the experience. I am trying to make the parser execute > JTRAN efficiently. > > And, most of us lapse into JTRAN occasionally. (maybe not Roger) > > Henry Rich > > > On 8/28/2021 11:37 PM, Elijah Stone wrote: > > On Sat, 28 Aug 2021, Henry Rich wrote: > > > >> Large improvement would require heroic intervention: parsing & > >> caching sentences on the fly & watching assignments to make sure the > >> cached parse is valid. I would rather avoid that. > > > > The technique has been implemented, to great effect - > > > http://www.softwarepreservation.org/projects/apl/Papers/DYNAMICINCREMENTAL > > > > That implementation placed the invalidation in the parsed (and > > compiled) sentence itself, rather than invalidating existing sentences > > on assignment, which simplified matters; before a sentence is > > executed, the inferred nameclasses of its referents are verified. > > This is much simpler and easier to get right, and retains similar > > performance (especially with modern branch predictors). > > > > That being said, if the parser is a bottleneck for some code, then it > > is likely doing something wrong and should perhaps not be encouraged :) > > > > -E > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
