Add tool for querying multiple installed package versions (#871)

* add tool for querying multiple installed package versions

* code review feedback

* handle base package

* don't try to get namespace info for base

Author: jmcphers

crates/ark/src/modules/positron/llm_tools.R

@@ -53,6 +53,25 @@
     res_list
 }
 
+#' Get the version of installed packages
+#'
+#' This function retrieves the versions of specified packages in R.
+#'
+#' It returns a named list where the names are the package names and the values
+#' are the corresponding package versions, or "Not installed" if the package is
+#' not found.
+#'
+#' @export
+.ps.rpc.get_package_versions <- function(package_names, ...) {
+    lapply(set_names(package_names), function(pkg) {
+        if (is_on_disk(pkg)) {
+            as.character(utils::packageVersion(pkg))
+        } else {
+            "Not installed"
+        }
+    })
+}
+
 #' Get available vignettes for a package
 #'
 #' This function retrieves the vignettes available for a specified package in R.

crates/ark/src/modules/positron/utils.R

@@ -152,3 +152,32 @@ obj_address <- function(x) {
 paste_line <- function(x) {
     paste(x, collapse = "\n")
 }
+
+set_names <- function(x, names = x) {
+    names(x) <- x
+    x
+}
+
+# From rlang
+is_on_disk <- function(pkg) {
+    system_path(pkg) != ""
+}
+
+system_path <- function(pkg) {
+    # Important for this to be first because packages loaded with pkgload
+    # will have a different path than the one in `.libPaths()` (if any).
+    #
+    # Note that this will not work for the base package, since we can't call
+    # getNamespaceInfo on it.
+    if (isNamespaceLoaded(pkg) && !identical(pkg, "base")) {
+        return(.getNamespaceInfo(asNamespace(pkg), "path"))
+    }
+
+    for (path in file.path(.libPaths(), pkg)) {
+        if (file.exists(path)) {
+            return(path)
+        }
+    }
+
+    ""
+}