listener: fix several bugs in auto compound expr mode.

* parser.c (repl): The first bug is that we are not correctly
checking the special variable: auto_parens holds the binding.
Thus TXR was behaving as if they feature is always enabled.
The second bug is that forms might not be a list; it could
be the colon symbol, so we cannot evaluate cdr(forms).
The third bug is that we don't want to create (progn . :)
when forms is the : symbol. These two bugs are reproduced
by turning on the mode and evaluating (1 2 3 . 4 5 6),
a bad form.

1 files changed, 5 insertions, 3 deletions

diff --git a/parser.c b/parser.c
index 53b05aa2..b1397576 100644
--- a/parser.c
+++ b/parser.c
@@ -1751,9 +1751,11 @@ val repl(val bindings, val in_stream, val out_stream, val env)
         counter = prev_counter;
       } else {
         val expr = if2(form != read_k,
-                       if3(auto_parens && cdr(forms),
-                           forms,
-                           cons(progn_s, forms)));
+                       if3(consp(forms),
+                           if3(cdr(auto_parens) && cdr(forms),
+                               forms,
+                               cons(progn_s, forms)),
+                           forms));
         val value = if3(form != read_k,
                         eval_intrinsic(expr, nil, env),
                         read_eval_ret_last(nil, prev_counter,