Variable init forms of for go inside nil block.

* eval.c (op_for): Establish the block before doing any
evaluation, subject to the compatibility option.

* txr.1: Updated documentation for for, exchanging
steps 1 and 2. Added compatibility notes.

1 files changed, 7 insertions, 3 deletions

diff --git a/eval.c b/eval.c
index 6d7710b0..174dc79d 100644
--- a/eval.c
+++ b/eval.c
@@ -1811,11 +1811,15 @@ static val op_for(val form, val env)
   val incs = fourth(form);
   val forms = rest(rest(rest(rest(form))));
   val new_env;
-  val new_bindings = bindings_helper(vars, env, eq(forsym, for_star_s),
-                                     &new_env, t, form);
+  int oldscope = opt_compat && opt_compat <= 123;
+
+  if (oldscope)
+    (void) bindings_helper(vars, env, eq(forsym, for_star_s), &new_env, t, form);
+
   uw_block_begin (nil, result);
 
-  (void) new_bindings;
+  if (!oldscope)
+    (void) bindings_helper(vars, env, eq(forsym, for_star_s), &new_env, t, form);
 
   for (; cond == nil || eval(car(cond), new_env, form);
        eval_progn(incs, new_env, form))