doc: codify infinite looping behavior of each.

* txr.1: the each, append-each and all other variants of
operators exhibit inifite looping if the list of bindings is
empty. In that case, the terminating condition that at least
one list is empty, is never true. The behavior is consistent
under compilation and interpretation, so let's just
document it.

1 files changed, 6 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index ecfe3219..443dedeb 100644
--- a/txr.1
+++ b/txr.1
@@ -15271,6 +15271,12 @@ determines the number of iterations, so if any of the
 evaluate to
 an empty list, the body is not executed.
 
+If the list of
+.cblk
+.meti >> ( syn  << init-form )
+.cble
+pairs itself is empty, then an infinite loop is specified.
+
 The body forms are enclosed in an anonymous block, allowing the
 .code return
 operator to terminate the loop prematurely and optionally specify