pretty much any use of =: (newrec ;reclookup) update assignwith 'database'
________________________________ From: Raul Miller <[email protected]> To: Programming forum <[email protected]> Sent: Tuesday, July 11, 2017 9:36 AM Subject: Re: [Jprogramming] Request for comments: multiple assignment In what sort of cases are in-place optimizations a relevant issue for assigning default values? Thanks, -- Raul On Tue, Jul 11, 2017 at 9:06 AM, 'Pascal Jasmin' via Programming <[email protected]> wrote: > The way I handle that, > > assignwithC > 2 : 0 > (y) =: u (y~ [ ]) :: (n"_) 1 > : > (y) =: x u (y~ [ ]) :: (n"_) 1 > ) > > > I think the call for =:: and =.. is based on 2 things. > > 1. Although defaults and "ORvals"/unassigned default values can be handled > easily enough through J expressions, for 805 anyway, it lost any inplace > optimizations. > > 2. it only works for =: and not =. > > > > ________________________________ > From: Marshall Lochbaum <[email protected]> > To: [email protected] > Sent: Tuesday, July 11, 2017 4:02 AM > Subject: Re: [Jprogramming] Request for comments: multiple assignment > > > Does this scheme support easily assigning a default value to a variable, > that is, assigning only if the name is currently unused? This is a > common case for me and I'm just now realizing that the "default" option > doesn't really do that. > > See https://github.com/mlochbaum/JSound/blob/master/wav.ijs for an > example, where I'm forced to write an awkward line of code to set the > default format to 16-bit 44.1kHz. This seems easy enough to support with > another trailing character on the name, like ^ or ?. So I would write > 'FMT? F?' =: 1 16;44100 > instead of the current version. > > On a side note, Earl Grey is a good language to look at if you are > interested in more sophisticated assignment schemes. I don't know if > much of it is relevant to J, but it's very cool to see what can happen > if you build a language to handle pattern matching from the bottom up. > See http://www.earl-grey.io/doc.html, up to the section on pattern > matching. > > Marshall > > On Tue, Jul 04, 2017 at 01:40:52AM -0400, 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 > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
