listDependencies.R

listDependencies <- function(pkgs){
  # Recursively looks through package dependencies (depends & imports) of a list of packages
  # Argument: a character vector of package names
  
  pack <- available.packages()
  pnames <- pack[,1]
  depmat <- matrix(ncol=3)
  
  while (TRUE){
    imports <- tools::package_dependencies(pack[pkgs[pkgs %in% pnames],], which = "Imports")
    depends <- tools::package_dependencies(pack[pkgs[pkgs %in% pnames],], which = "Depends")
    
    for (i in imports){
      if (is.matrix(i)) depmat <- rbind(depmat,i)
    }
    for (d in depends){
      if (is.matrix(d)) depmat <- rbind(depmat,d)
    }
    
    if (all(pkgs %in% unique(depmat[-1,1]))){
      break
    }
    
    pkgs <- unique(depmat[-1,1])
    depmat <- unique(depmat)
  }
  
  sortmat <- unique(depmat[-1,])[order(unique(depmat)[-1,1], unique(depmat)[-1,3]),]
  pkglist <- unname(sortmat[!duplicated(sortmat[,1], fromLast = T),])
  
  return(pkglist)
}