Don't fake empty cells value by "" when printing with a lambda.

When using a lambda expression printer function the user should be
free to format differently a really empty cell, ie. containing nil,
from a cell containing an empty string "".

* ses.el (ses-call-printer): Replace `(or value "")' by just `value'
in the case of a lambda expression printer function.

* ses.texi (Printer functions): Add example and description about
lambda expression printer function handling all the possible values,
including unexpected ones.

1 files changed, 1 insertions, 1 deletions

diff --git a/lisp/ses.el b/lisp/ses.el
index 7347eb8f5fd..8cbc2e80cde 100644
--- a/lisp/ses.el
+++ b/lisp/ses.el
@@ -1289,7 +1289,7 @@ printer signaled one (and \"%s\" is used as the default printer), else nil."
                           (and locprn
                                (ses--locprn-compiled locprn))))
                    printer)
-               (or value "")))
+               value))
         (if (stringp value)
             value
           (or (stringp (car-safe value))