Add whichExecutables()

Author: hsonne

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: kwb.utils
 Title: General Utility Functions Developed at KWB
-Version: 0.15.0
+Version: 0.15.0.9000
 Authors@R: 
     c(person(given = "Hauke",
              family = "Sonnenberg",
@@ -32,4 +32,4 @@ Suggests:
 VignetteBuilder: 
     knitr
 Encoding: UTF-8
-RoxygenNote: 7.3.1
+RoxygenNote: 7.3.2

NEWS.md

@@ -1,3 +1,7 @@
+# Latest Changes
+
+- add whichExecutables()
+
 # [kwb.utils 0.15.0](https://github.com/KWB-R/kwb.utils/releases/tag/v0.15.0) <small>2024-03-28</small>
 
 - add loadFunctions() with private function

R/whichExecutables.R

@@ -0,0 +1,30 @@
+#' Find Executable Files in Directories given in PATH Environment Variable
+#' 
+#' @param pattern if not NULL, the result list is filtered for file names 
+#'   matching the pattern
+#' @param full.names if TRUE, the list items are the full paths, otherwise the
+#'   file names only
+#' @return list with one entry per directory from the PATH variable
+whichExecutables <- function(pattern = NULL, full.names = FALSE)
+{
+  paths <- kwb.utils::rStylePath(strsplit(Sys.getenv("PATH"), ";")[[1]])
+  extensions <- strsplit(Sys.getenv("PATHEXT"), ";")[[1L]]
+  ext_patterns <- gsub("\\.", "\\\\.", extensions)
+  ext_pattern <- sprintf("(%s)$", paste(ext_patterns, collapse = "|"))
+  exe_files <- lapply(
+    stats::setNames(nm = paths), 
+    FUN = dir, 
+    pattern = ext_pattern, 
+    ignore.case = TRUE
+  )
+  if (!is.null(pattern)) {
+    exe_files <- lapply(exe_files, grep, pattern = pattern, value = TRUE)
+    exe_files <- exe_files[lengths(exe_files) > 0L]
+  }
+  if (full.names) {
+    exe_files <- lapply(stats::setNames(nm = names(exe_files)), function(path) {
+      file.path(path, exe_files[[path]])
+    })  
+  }
+  exe_files
+}