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.

2 files changed, 21 insertions, 9 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))
diff --git a/txr.1 b/txr.1
index b7e1b202..c2f25772 100644
--- a/txr.1
+++ b/txr.1
@@ -12502,6 +12502,11 @@ and
 operators execute these steps:
 .RS
 .IP 1.
+Establish an anonymous block over the entire form, allowing
+the
+.code return
+operator to be used to terminate the loop.
+.IP 2.
 Establish bindings for the specified variables similarly to
 .code let
 and
@@ -12514,11 +12519,6 @@ each
 .meta inc-form
 and each
 .metn body-form .
-.IP 2.
-Establish an anonymous block over the remaining forms, allowing
-the
-.code return
-operator to be used to terminate the loop.
 .IP 3.
 Evaluate
 .metn test-form .
@@ -37341,7 +37341,15 @@ of these version values, the described behaviors are provided if
 is given an argument which is equal or lower. For instance
 .code -C 103
 selects the behaviors described below for version 105, but not those for 102.
-
+.IP 123
+In \*(TX 123 and earlier, the variable initialization forms of a
+.code for
+or
+.code for*
+loop were evaluated outside of the scope of the implicit
+.code nil
+block. They are now inside the block. The compatibility option will
+restore the old behavior.
 .IP 121
 In \*(TX 121 and earlier versions, \*(TL expressions evaluated in the
 pattern language were placed in a lexical environment in which the