Some extra helper functions

scrbl/racket-makefile.scrbl

@@ -5,6 +5,7 @@
                      (only-in racket-makefile
                               target deps phony default-target make
                               run rm-f rm-rf cleanup
+                              list-dir/files list-files list-dirs
                               $target $deps $<)))
 
 @title{racket-makefile}
@@ -31,7 +32,7 @@ raco pkg install
 For a versioned archive, specify the package name explicitly:
 
 @verbatim{
-raco pkg install --name racket-makefile racket-makefile-0.1.2.zip
+raco pkg install --name racket-makefile racket-makefile-0.1.4.zip
 }
 
 After installation a makefile can start with:
@@ -224,6 +225,59 @@ For example:
              "**.css")))
 ]
 
+@section{Regexp directory helpers}
+
+@defproc[(list-dir/files [directory path-string?]
+                         [regexp regexp?]
+                         [#:recursive recursive any/c #f])
+         list?]{
+Returns entries below @racket[directory] that match @racket[regexp]. By default
+only the direct contents of @racket[directory] are inspected. With
+@racket[#:recursive #t], the complete tree is walked using
+@racket[in-directory], and both files and directories can be returned.
+
+For a non-recursive listing, complete paths are built from @racket[directory],
+so the result can be passed directly to file operations such as
+@racket[rm-f] and @racket[rm-rf].
+}
+
+@defproc[(list-files [directory path-string?]
+                     [regexp regexp?]
+                     [#:recursive recursive any/c #f])
+         list?]{
+Like @racket[list-dir/files], but keeps only paths for which
+@racket[file-exists?] is true.
+}
+
+@defproc[(list-dirs [directory path-string?]
+                    [regexp regexp?]
+                    [#:recursive recursive any/c #f])
+         list?]{
+Like @racket[list-dir/files], but keeps only paths for which
+@racket[directory-exists?] is true.
+}
+
+These helpers make regexp-based cleanup concise. For example:
+
+@racketblock[
+(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."))
+]
+
+The second regular expression is case-insensitive and matches names ending in
+@tt{.bak} or @tt{~}.
+
 @section{Using ordinary Racket}
 
 No separate make programming language is introduced. Definitions, functions,