gexp: Add #:select? parameter to 'local-file'.

* guix/gexp.scm (<local-file>)[select?]: New field.
(true): New procedure.
(%local-file): Add #:select? and honor it.
(local-file): Likewise.
* tests/gexp.scm ("local-file, #:select?"): New test.
* doc/guix.texi (G-Expressions): Adjust accordingly.

1 files changed, 6 insertions, 1 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index f85221d065..227d861482 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -3804,7 +3804,7 @@ does not have any effect on what the G-expression does.
 content is directly passed as a string.
 
 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
-   [#:recursive? #f]
+   [#:recursive? #f] [#:select? (const #t)]
 Return an object representing local file @var{file} to add to the store; this
 object can be used in a gexp.  If @var{file} is a relative file name, it is looked
 up relative to the source file where this form appears.  @var{file} will be added to
@@ -3814,6 +3814,11 @@ When @var{recursive?} is true, the contents of @var{file} are added recursively;
 designates a flat file and @var{recursive?} is true, its contents are added, and its
 permission bits are kept.
 
+When @var{recursive?} is true, call @code{(@var{select?} @var{file}
+@var{stat})} for each directory entry, where @var{file} is the entry's
+absolute file name and @var{stat} is the result of @code{lstat}; exclude
+entries for which @var{select?} does not return true.
+
 This is the declarative counterpart of the @code{interned-file} monadic
 procedure (@pxref{The Store Monad, @code{interned-file}}).
 @end deffn