Merge pull request #37 from JuliaStats/expand_readme

Expand README.md

README.md

@@ -1,4 +1,4 @@
-# RData
+# RData.jl
 
 [![Julia 0.6 Status](http://pkg.julialang.org/badges/RData_0.6.svg)](http://pkg.julialang.org/?pkg=RData&ver=0.6)
 
@@ -10,6 +10,16 @@ Read R data files (.rda, .RData) and optionally convert the contents into Julia
 
 Can read any R data archive, although not all R types could be converted into Julia.
 
+For running R code from Julia see [RCall.jl](https://github.com/JuliaInterop/RCall.jl).
+
+Installation
+------------
+
+From Julia REPL:
+```julia
+Pkg.add("RData")
+```
+
 Usage
 -----
 
@@ -20,13 +30,16 @@ using RData
 objs = load("path_to/example.rda")
 ```
 
-The result is a dictionary of all R objects that are stored in "example.rda".
+The result is a dictionary (`Dict{String, Any}`) of all R objects stored in "example.rda".
 
 If `convert=true` keyword option is specified, `load()` will try to automatically
 convert R objects into Julia equivalents:
- * data frames into `DataFrames.DataFrame`
- * named vectors into `DictoVec` objects that allow indexing both by element indices and by names
- * ...
 
-If the conversion to Julia type is not supported (e.g. R closure or language expression),
-the internal RData representation of the object will be provided.
+| R object     | Julia object           |  |
+|--------------|------------------------|--|
+| named vector, list | `DictoVec` | `DictoVec` allows indexing both by element index and by its name, just as R vectors and lists |
+| vector    | `Vector{T}` | `T` is the appropriate Julia type. If R vector contains `NA` values, they are converted to [`missing`](https://github.com/JuliaData/Missings.jl), and the elements type of the resulting `Vector` is `Union{T, Missing}`.
+| factor     | `CategoricalArray` | [CategoricalArrays.jl](https://github.com/JuliaData/CategoricalArrays.jl) |
+| data frame | `DataFrame` | [DataFrames.jl](https://github.com/JuliaData/DataFrames.jl) |
+
+If conversion to the Julia type is not supported (e.g. R closure or language expression), `load()` will return the internal RData representation of the object (`RSEXPREC` subtype).