For example, here's a code snippet from R: function (x, data) eval(x$expr, data, x$env)
x is an expression which contains an environment attribute. It is evaluated first checking the bindings in data (data being a dataframe) and then checing the bindings in x's environment. On Wednesday, July 8, 2015 at 3:37:04 PM UTC-4, Brandon Taylor wrote: > > *reifying. Deifying environments might not be the best idea. > > On Wednesday, July 8, 2015 at 3:34:53 PM UTC-4, Brandon Taylor wrote: >> >> 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 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 >>> <https://www.google.com/url?q=https%3A%2F%2Fgithub.com%2FJuliaStats%2FDataFrames.jl%2Fissues%2F504&sa=D&sntz=1&usg=AFQjCNHgUEZP8TyJ_BuUyyFA5SIxneOJTA> >>> >>> 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? >>>> >>>
