lib: basic support for trees as sequences.

As of this commit, binary search trees can be iterated:
mapped over with mapcar and such.

* arith.c (poly, rpoly): rpoly won't work with trees. They
work just with vectors and lists so let's make the error
message more accurate. I noticed the self names of these two
are swapped; will fix in another commit.

* eval.c (tprint): Refactor to use iterator framework for
objects other than lists. The tree case falls into this,
so trees are supported.

* lib.h (enum seq_kind): New enum constant SEQ_TREELIKE.
(seq_iter_init_with_info): Declared.

* lib.c (seq_info): Map tree object to SEQ_TREELIKE type.
(seq_iter_get_tree, seq_iter_peek_tree): New static functions.
(seq_iter_rewind): Support rewinding tree iteration.
I think we could reuse the existing iterator here, and in the
hash case as well. I made a note to look into this.
(seq_iter_init_with_info): Internal linkage changed to
external, because tprint in eval.c uses this.
Handle SEQ_TREELIKE case here, by setting up iterator with the
two new static functions.
(seq_iter_mark): Handle SEQ_TREELIKE_CASE. Change switch
statement to exhaustively list cases.
(ldiff): Add SEQ_TREELIKE to various cases. Idea is that we
handle it like SEQ_HASH.
(nsort, sort, nshuffle, take, take_while, take_until,
drop_while, drop_until, update): Add case for SEQ_TREELIKE,
routing to error message.
(lazy_where_tree_func): New static function.
(where, sel, reject): Support trees.

1 files changed, 18 insertions, 12 deletions

diff --git a/eval.c b/eval.c
index 814f99c5..47561afb 100644
--- a/eval.c
+++ b/eval.c
@@ -6278,13 +6278,15 @@ val tprint(val obj, val out)
 
   switch (si.kind) {
   case SEQ_NIL:
-    break;
+    return nil;
   case SEQ_LISTLIKE:
+    if (consp(si.obj))
     {
       gc_hint(si.obj);
       gc_hint(obj);
       for (obj = z(si.obj); !endp(obj); obj = cdr(obj))
         tprint(car(obj), out);
+      return nil;
     }
     break;
   case SEQ_VECLIKE:
@@ -6293,23 +6295,27 @@ val tprint(val obj, val out)
     case STR:
     case LSTR:
       put_line(obj, out);
-      break;
+      return nil;
     default:
-      {
-        val vec = si.obj;
-        cnum i, len = c_fixnum(length(vec), self);
-
-        for (i = 0; i < len; i++)
-          tprint(ref(vec, num_fast(i)), out);
-
-      }
       break;
     }
     break;
-  case SEQ_NOTSEQ:
+  case SEQ_TREELIKE:
+    break;
   case SEQ_HASHLIKE:
+  case SEQ_NOTSEQ:
     pprinl(obj, out);
-    break;
+    return nil;
+  }
+
+  {
+    seq_iter_t iter;
+    val elem;
+
+    seq_iter_init_with_info(self, &iter, si, 0);
+
+    while (seq_get(&iter, &elem))
+      tprint(elem, out);
   }
 
   return nil;