1 files changed, 4 insertions, 0 deletions
diff --git a/doc.txt b/doc.txt
index fce7e9d..d65c981 100644
--- a/doc.txt
+++ b/doc.txt
@@ -43,6 +43,10 @@
 	(arr): create new empty array
 	(append a x): appends to array a, returns a
 	(len a): get length of array a
+	(, ...): pend. concatenates arrays, promotes non-arrays to arrays
+				(, [1 2 3] 4) -> [1 2 3 4]
+				(, [1 2 3] [4 5]) -> [1 2 3 4 5]
+				(, 10 20) -> [10 20]  etc
 
 # cmdline args
 	bth [-Dl] [-Dt] filenames...