match: ^#S() and ^#H(()) patterns must work

Quasiquote patterns not containing unquotes are not
working, because the parser transforms them into
quoted objects. For instance ^#S(time) becomes
the form (quote #S(time)) and not the
form (sys:qquote (sys:struct-lit time)).
The pattern matching compiler doesn't treat quote
specially, only sys:qquote.

* parser.y (unquotes_occur): Function removed.
(vector, hash, struct, tree, json_vals, json_pairs):
Remove use of unquotes_occur. Thus vector, hash,
struct, tree and JSON syntax occurring within a
backquote will be turned into a special literal
whether or not it contains unquotes.

* lib.c (obj_print_impl): Do not print the
form (sys:hash-lit) as #Hnil, but #H().

* stdlib/match.tl (transform-qquote): Add a case
which will handle ^#H(), as if it were ^H(()).
Bugfix in the ^H(() ...) case. The use of @(coll)
means it fails to match the empty syntax when
no key/value pairs are specified, whereas
@(all) respects vacuous truth.

* test/011/patmatch.tl: A few tests.

* y.tab.shipped, y.tab.h.shipped: Updated.

1 files changed, 5 insertions, 2 deletions

diff --git a/lib.c b/lib.c
index e995fcf0..417109dd 100644
--- a/lib.c
+++ b/lib.c
@@ -14260,10 +14260,13 @@ val obj_print_impl(val obj, val out, val pretty, struct strm_ctx *ctx)
         obj_print_impl(arg, out, pretty, ctx);
       } else if (sym == hash_lit_s) {
         put_string(lit("#H"), out);
-        obj_print_impl(rest(obj), out, pretty, ctx);
+        if (!args)
+          put_string(lit("()"), out);
+        else
+          obj_print_impl(args, out, pretty, ctx);
       } else if (sym == struct_lit_s) {
         put_string(lit("#S"), out);
-        obj_print_impl(rest(obj), out, pretty, ctx);
+        obj_print_impl(args, out, pretty, ctx);
       } else if (sym == json_s && have_args &&
                  consp(cdr(args)) && nilp(cddr(args)))
       {