bugfix: quasilit read/print consistency, part 1.

The bug is that `@@@a` prints as `@@a` which
reads as a different object.

In this patch we simplify how quasiliterals are represented.
Embedded expressions are no longer (sys:expr E), just E.
Meta-numbers N and variables V are still (sys:var N).

However `@@a` and `@a` remain equivalent.

* eval.c (subst_vars): No need to look for expr_s;
just evaluate a compound form. The recursive nested
case is unnecessary and is removed.
(expand_quasi): Do nothandle expr_s; it is not
part of the quasi syntax any more.

* lib.c (out_quasi_str): Do not look for expr_s in the
quasi syntax; just print any expression with a @
the fallback case.

* match.c (tx_subst_vars): Analogous changes to those
done in subst_vars in eval.c.

* parser.y (quasi_meta_helper): Static function removed.
This was responsible for the issue due to stripping a
level of meta from expressions already having a meta
on them.
(quasi_item): In the `@` n_expr syntax case, no longer
call quasi_meta_helper. The remaining logic is simple
enough to put in line. Symbols and integers get wrapped
with (sys:var ...); other expressions are integrated
into the syntax as-is.

1 files changed, 3 insertions, 8 deletions

diff --git a/match.c b/match.c
index d9df8764..93b84a07 100644
--- a/match.c
+++ b/match.c
@@ -1493,13 +1493,13 @@ static val tx_subst_vars(val spec, val bindings, val filter)
           iter = list_collect_append(iter, nested);
           spec = cdr(spec);
           continue;
-        } else if (sym == expr_s) {
+        } else {
           if (opt_compat && opt_compat < 100) {
-            val result = tleval(spec, rest(elem), bindings);
+            val result = tleval(spec, elem, bindings);
             spec = cons(filter_string_tree(filter, tostringp(result)), rest(spec));
             continue;
           } else {
-            val str = tleval(spec, rest(elem), bindings);
+            val str = tleval(spec, elem, bindings);
             if (listp(str))
               str = cat_str(mapcar(func_n1(tostringp), str), lit(" "));
             else if (!stringp(str))
@@ -1507,11 +1507,6 @@ static val tx_subst_vars(val spec, val bindings, val filter)
             spec = cons(filter_string_tree(filter, tostringp(str)), rest(spec));
             continue;
           }
-        } else {
-          val nested = tx_subst_vars(elem, bindings, filter);
-          iter = list_collect_append(iter, nested);
-          spec = cdr(spec);
-          continue;
         }
       }