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, 4 insertions, 1 deletions

diff --git a/lib.h b/lib.h
index cb1b2ef6..70ba864a 100644
--- a/lib.h
+++ b/lib.h
@@ -499,7 +499,7 @@ extern val query_error_s, file_error_s, process_error_s, syntax_error_s;
 extern val timeout_error_s, system_error_s, alloc_error_s;
 extern val warning_s, defr_warning_s, restart_s, continue_s;
 extern val gensym_counter_s;
-extern val rplaca_s, rplacd_s;
+extern val rplaca_s, rplacd_s, seq_iter_s;
 
 #define gensym_counter (deref(lookup_var_l(nil, gensym_counter_s)))
 
@@ -532,6 +532,9 @@ seq_info_t seq_info(val cobj);
 void seq_iter_init(val self, seq_iter_t *it, val obj);
 void seq_iter_rewind(val self, seq_iter_t *it);
 INLINE int seq_get(seq_iter_t *it, val *pval) { return it->get(it, pval); }
+val seq_begin(val obj);
+val seq_next(val iter, val end_val);
+val seq_reset(val iter, val obj);
 val throw_mismatch(val self, val obj, type_t);
 INLINE val type_check(val self, val obj, type_t typecode)
 {