Some extra helper functions

private/commands.rkt

@@ -10,7 +10,10 @@
 (provide run
          rm-f
          rm-rf
-         cleanup)
+         cleanup
+         list-dir/files
+         list-files
+         list-dirs)
 
 (define (recipe-value who parameter description)
   (define value (parameter))
@@ -80,3 +83,19 @@
       [(file link) (rm-f path)]
       [else (void)]))
   (void))
+
+(define (list-dir/files directory regexp #:recursive [recursive #f])
+  (filter (lambda (path)
+            (regexp-match? regexp path))
+          (if recursive
+              (for/list ([path (in-directory directory)])
+                path)
+              (directory-list directory #:build? #t))))
+
+(define (list-files directory regexp #:recursive [recursive #f])
+  (filter file-exists?
+          (list-dir/files directory regexp #:recursive recursive)))
+
+(define (list-dirs directory regexp #:recursive [recursive #f])
+  (filter directory-exists?
+          (list-dir/files directory regexp #:recursive recursive)))