I agree with Don's suggestion. I've also found things like "++" to be a little notational wart in the C; it extends to "--", both pre- and post-fix forms, but is similar to nothing else in the language. Learning about it gives you nothing of value that's generally applicable elsewhere.
On Wed, Jul 5, 2017 at 1:44 PM, Don Kelly <[email protected]> wrote: > Why? Is this accomplishing anything ? Is the value of t changed? > > t=:1 2 3 > > t+3 or 3+t give 4 5 6 but t is not changed > > to have a change in t then t=:t+3 works and its meaning is clear. > > I would suggest that the value of J (as with APL) is that it is not C and > non-C thinking is a benefit. > > Don Kelly > > > > > On 2017-07-04 10:55 AM, 'Mike Day' via Programming wrote: > >> Not multiple assignment, but copula-related. >> >> I've often wondered why J doesn't have the C family feature of assignments >> such as >> t =: 1 2 3 >> [t+=: 3 >> 4 5 6 >> >> I don't know what it's called, and I realise it's only an arguably >> attractive >> feature, not an essential one, but would be useful, especially when >> translating >> (or plagiarising) to J from C-like code. >> >> John Scholes et al managed to include it in Dyalog APL many years ago; >> it's >> in his "dfns" (dynamic functions, I think) as well as their more >> conventional >> APL functions and session operations. If I recall correctly, John spells >> out rules >> for passing values to variables of local scope within dfns using such >> operators. >> >> Dyalog doesn't have constructs like t++, though. >> >> Thanks, >> Mike >> >> On 04/07/2017 06:40, HenryRich wrote: >> >>> Here is a feature that I have wanted for a long time: >>> >>> http://code.jsoftware.com/wiki/System/Interpreter/Requests# >>> Expanded_Multiple_Assignment >>> >>> It attempts to solve the problem of moving verb arguments into >>> variable-names. Allows defaults and multilevel arguments. I will >>> implement this within a month or so, so get your comments in ASAP. >>> >>> Henry Rich >>> >>> --- >>> This email has been checked for viruses by AVG. >>> http://www.avg.com >>> >>> ---------------------------------------------------------------------- >>> For information about J forums see http://www.jsoftware.com/forums.htm >>> >> >> >> --- >> This email has been checked for viruses by Avast antivirus software. >> https://www.avast.com/antivirus >> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA Quantitative Consultant ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
