Some extra helper functions

README.md

@@ -40,7 +40,7 @@ raco pkg install
 For a versioned archive, give the package name explicitly:
 
 ```text
-raco pkg install --name racket-makefile racket-makefile-0.1.2.zip
+raco pkg install --name racket-makefile racket-makefile-0.1.4.zip
 ```
 
 ## Running targets
@@ -78,6 +78,36 @@ registers the targets. Then use the Interactions window:
 Bare identifiers in `make` are target names, so no quote is needed. For
 example, `(make clean)` selects the target named `clean`.
 
+## Regexp-based cleanup
+
+For cleanup rules that need more control than globs, `racket-makefile` also
+provides small directory/regexp helpers. The results are ordinary path lists,
+so they can be passed directly to `rm-f` and `rm-rf` with `apply`:
+
+```racket
+#lang racket-makefile
+
+(default-target all)
+(phony all clean)
+
+(target all
+  (displayln "use (make clean)"))
+
+(target clean
+  (display "cleaning up...")
+  (apply rm-rf
+         (list-dirs "." #px"compiled$" #:recursive #t))
+  (apply rm-f
+         (list-files "." #px"(?i:(?:[.]bak|~)$)" #:recursive #t))
+  (displayln "done."))
+```
+
+`list-dir/files` returns matching files and directories. `list-files` and
+`list-dirs` restrict the result to files or directories. All three scan one
+directory level by default; use `#:recursive #t` to walk the complete tree.
+Non-recursive results are returned as complete paths, so the lists can be fed
+directly to `rm-f` or `rm-rf` with `apply`.
+
 ## Generated targets
 
 Because the rest of the language is ordinary Racket, targets can be generated
@@ -101,7 +131,7 @@ with normal definitions and loops:
 Dependency expressions may produce lists; they are recursively flattened.
 
 The language adds `target`, `deps`, `phony`, `default-target`, `make`, `run`,
-`rm-f`, `rm-rf`, `cleanup`, `$target`, `$deps` and `$<`. Everything else is
-ordinary Racket.
+`rm-f`, `rm-rf`, `cleanup`, `list-dir/files`, `list-files`, `list-dirs`,
+`$target`, `$deps` and `$<`. Everything else is ordinary Racket.
 
 See the installed `racket-makefile` Scribble documentation for the full API.