for/for*: stricter syntax check.

* eval.c (me_for): Require at least one argument.
However, we let the init-forms continue to be optional
and document it.

* txr.1: Refer to for and for* as macros, since they have been
since 2016. The omission of the inc-form list is shown
as a second variant of the syntax. This is to avoid misleading
the reader into thinking that the the inc-form list can be
omitted while body forms are present. A spurious paragraph
reiterating that the macros establish an anonymous block is
removed. That extra text was present in the first draft written
in 2011, and maintained since.

* stdlib/doc-syms.tl: Updated.

1 files changed, 1 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index 4053f8eb..7f207de9 100644
--- a/eval.c
+++ b/eval.c
@@ -3215,7 +3215,7 @@ static val me_each(val form, val menv)
 static val me_for(val form, val menv)
 {
   val forsym = first(form);
-  val args = (syn_check(form, forsym, cdr, 0), rest(form));
+  val args = (syn_check(form, forsym, cddr, 0), rest(form));
   val vars = first(args);
   val body = rest(args);
   int oldscope = opt_compat && opt_compat <= 123;