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, 2 insertions, 2 deletions

diff --git a/lib.c b/lib.c
index 641b7337..c510ba73 100644
--- a/lib.c
+++ b/lib.c
@@ -9481,9 +9481,9 @@ static void out_quasi_str(val args, val out, struct strm_ctx *ctx)
         }
         if (need_brace)
           put_char(chr('}'), out);
-      } else if (sym == expr_s) {
+      } else {
         put_char(chr('@'), out);
-        obj_print_impl(rest(elem), out, nil, ctx);
+        obj_print_impl(elem, out, nil, ctx);
       }
     } else {
       obj_print_impl(elem, out, nil, ctx);