What's the argument against using R and dropping into RCpp for very limited tasks? I (helped) write a very widely used R modelling package and while I wasn't doing anything on the numerical side, we seemed to get great performance from this approach -- and workflow-wise it wasn't too dissimilar to 25 years ago where I had to occasionally drop in X86 assembly to speed up C code!
(Not a hater of Julia at all, very much think it's a cool language and an increasingly vibrant ecosystem and have been consistently impressed when Julia devs have spoke at events I've attended)
(Not a hater of Julia at all, very much think it's a cool language and an increasingly vibrant ecosystem and have been consistently impressed when Julia devs have spoke at events I've attended)