X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/blobdiff_plain/ca8f5d55bfc2b792edeb00e48d970b5b6b6c2c9b..b07535d86a625c99240d8fdc46d589f5cc03a29c:/doc/syntax.tex

diff --git a/doc/syntax.tex b/doc/syntax.tex
index 0e14e17..a1b650c 100644
--- a/doc/syntax.tex
+++ b/doc/syntax.tex
@@ -743,6 +743,10 @@ Properties for the @|custom| aggregating method combination:
 \item[@"before"] A code fragment containing initialization to be performed at
   the beginning of the effective method body.  The default is to insert
   nothing.
+\item[@"empty"] A code fragment executed if there are no primary methods;
+  it should usually store a suitable (identity) value in @<retvar>.  The
+  default is not to emit an effective method at all if there are no primary
+  methods.
 \item[@"first"] A code fragment to set the return value after calling the
   first applicable direct method.  The default is to use the @"each"
   fragment.