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? >
