Allow quasi-quoting over hash table literals,

to express dynamic hash table construction

* eval.c (expand_qquote): Recognize hash-construct
forms: expand the hash arguments and pairs separately,
then rewrite to a new hash-construct form.
(eval-init): hash-construct intrinsic function added.

* hash.c (hash_construct_s): New symbol variable.
(hash_construct): New function.
(hash_init): Initialize hash_construct_s.

* hash.h (hash_construct_s, hash_construct): Declared.

* parser.y (hash): Rule rewritten to emit either a literal
hash table object, or a hash-construct form, based on
whether quasiquote unquotes occur within the syntax.
(hash_from_notation): Function removed.

1 files changed, 14 insertions, 0 deletions

diff --git a/hash.c b/hash.c
index bc086ae9..713034c7 100644
--- a/hash.c
+++ b/hash.c
@@ -65,6 +65,7 @@ struct hash_iter {
 };
 
 val weak_keys_k, weak_vals_k, equal_based_k;
+val hash_construct_s;
 
 /*
  * Dynamic list built up during gc.
@@ -580,9 +581,22 @@ val hashv(val args)
   return make_hash(wkeys, wvals, equal);
 }
 
+val hash_construct(val hashv_args, val pairs)
+{
+  val hash = hashv(hashv_args);
+
+  for (; pairs; pairs = cdr(pairs)) {
+    val pair = car(pairs);
+    sethash(hash, first(pair), second(pair));
+  }
+
+  return hash;
+}
+
 void hash_init(void)
 {
   weak_keys_k = intern(lit("weak-keys"), keyword_package);
   weak_vals_k = intern(lit("weak-vals"), keyword_package);
   equal_based_k = intern(lit("equal-based"), keyword_package);
+  hash_construct_s = intern(lit("hash-construct"), user_package);
 }