I'm not sure I understand...
On Wednesday, July 8, 2015 at 6:24:37 PM UTC-4, John Myles White wrote: > > Reified scope makes static analysis much too hard. Take any criticism of > mutable state: they all apply to globally mutable symbol tables. > > On Wednesday, July 8, 2015 at 10:26:23 PM UTC+2, Milan Bouchet-Valat wrote: >> >> Le mercredi 08 juillet 2015 à 13:20 -0700, Brandon Taylor a écrit : >> > All functions. >> Well, I don't know of any language which doesn't have scoping rules... >> >> Anyway, I didn't say scoping rules are necessarily confusing, I was >> only referring to R formulas. But according to the examples you posted, >> your question appears to be different. >> >> >> Regards >> >> > On Wednesday, July 8, 2015 at 4:18:09 PM UTC-4, Milan Bouchet-Valat >> > wrote: >> > > Le mercredi 08 juillet 2015 à 12:57 -0700, Brandon Taylor a écrit : >> > > >> > > > If scoping rules are too complicated and cause confusion, why are >> > > >> > > > they built into the base implementation of function? >> > > What do you mean? Which function? >> > > >> > > > On Wednesday, July 8, 2015 at 3:48:52 PM UTC-4, Milan Bouchet >> > > -Valat >> > > > wrote: >> > > > > Le mercredi 08 juillet 2015 à 12:34 -0700, Brandon Taylor a >> > > écrit : >> > > > > >> > > > > > I was aware of those packages (though I hadn't read the >> > > > > discussions >> > > > > > referenced). Macros are great but they are incredibly >> > > difficult >> > > > > to >> > > > > > reason with concerning issues of scope (at least for me). >> > > > > Deifying >> > > > > > environments could solve all of these issues (and so much >> > > more) >> > > > > in >> > > > > > one fell swoop. >> > > > > On the contrary, I think well-designed macros can be much >> > > easier to >> > > > > >> > > > > think about than environments in R. If the macro takes a >> > > DataFrame >> > > > > object and an expression, there's no ambiguity about what the >> > > scope >> > > > > is. >> > > > > This is even better if variables that should be found in the >> > > data >> > > > > frame >> > > > > are passed as symbols, like :var, while standard variables are >> > > > > specified as usual. >> > > > > >> > > > > On the other hand, I find R formulas too flexible and complex >> > > to >> > > > > reason >> > > > > about. You never know whether an object will be found in the >> > > > > formula's >> > > > > environment, in one of the parent environments of the >> > > > > function/package >> > > > > you called, in your function, or in the global environment. >> > > > > >> > > > > >> > > > > Regards >> > > > > >> > > > > > On Wednesday, July 8, 2015 at 3:20:00 PM UTC-4, David Gold >> > > wrote: >> > > > > >> > > > > > > Some of these issues have been thought about fairly >> > > extensively >> > > > > by >> > > > > > > the stats community in particular, precisely on account of >> > > the >> > > > > use >> > > > > > > cases you cite: >> > > > > > > >> > > > > > > https://github.com/JuliaStats/DataFrames.jl/pull/472 >> > > > > > > https://github.com/JuliaStats/DataFrames.jl/issues/504 >> > > > > > > >> > > > > > > I think that the matter is still very much an open >> > > question. I >> > > > > have >> > > > > > > no sense that anything is going to be added to Base Julia >> > > > > itself. >> > > > > > > Currently, the best way (that I know of, anyway) to achieve >> > > the >> > > > > >> > > > > > > delayed evaluation effect is via the use of macros. See for >> > > >> > > > > > > instance: >> > > > > > > >> > > > > > > https://github.com/JuliaStats/DataFramesMeta.jl >> > > > > > > https://github.com/one-more-minute/Lazy.jl >> > > > > > > >> > > > > > > I'm hope somebody else will be able to pop in an give a >> > > more >> > > > > > > thorough answer, but the above may at least be a place to >> > > > > start. >> > > > > > > >> > > > > > > On Wednesday, July 8, 2015 at 2:03:45 PM UTC-4, Brandon >> > > Taylor >> > > > > > > wrote: >> > > > > > > > Hadley Wickham's lazyeval package in R is pretty cool in >> > > that >> > > > > you >> > > > > > > > can attach an environment to an expression, pass it in >> > > and >> > > > > out of >> > > > > > > > functions with various modifications, and then evaluate >> > > the >> > > > > > > > expression within the original environment (or any other >> > > > > > > > environment that you choose). R in general has the >> > > functions >> > > > > like >> > > > > > > > list2env and list(environment()) that allow one to >> > > convert an >> > > > > >> > > > > > > > environment into a list and back again (list being the R >> > > > > > > > equivalent of a Dict). Are there any plans to add these >> > > kind >> > > > > of >> > > > > > > > features to Julia? >> > > > > > > > >> >
