New sequence iterator object and functions.

* eval.c (eval_init): Register seq-begin, seq-next and
seq-reset.

* lib.c (seq_iter_s): New symbol variable.
(seq_iter_mark): New static function.
(seq_iter_ops): New static structure.
(seq_begin, seq_next, seq_reset): New functions.
(obj_init): Intern seq-iter symbol, used as class name for
iterators.

* lib.h (seq_iter_s, seq_begin, seq_next, seq_reset):
Declared.

* txr.1: Documented.

1 files changed, 3 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index a3b593ef..b628257d 100644
--- a/eval.c
+++ b/eval.c
@@ -6858,6 +6858,9 @@ void eval_init(void)
   reg_fun(intern(lit("where"), user_package), func_n2(where));
   reg_fun(intern(lit("select"), user_package), func_n2(sel));
   reg_fun(intern(lit("relate"), user_package), func_n3o(relate, 2));
+  reg_fun(intern(lit("seq-begin"), user_package), func_n1(seq_begin));
+  reg_fun(intern(lit("seq-next"), user_package), func_n2(seq_next));
+  reg_fun(intern(lit("seq-reset"), user_package), func_n2(seq_reset));
 
   reg_fun(intern(lit("rcons"), user_package), func_n2(rcons));
   reg_fun(intern(lit("rangep"), user_package), func_n1(rangep));