New function: iterp.

* eval.c (eval_init): Register iterp intrinsic.

* lib.[ch] (iterp): New function.

* tests/012/iter.tl: New tests.

* txr.1: Document iterp. Update documentation for iter-more,
iter-item and iter-step to more precisely identify which
objects are valid arguments in terms of iterp and additional
conditions, and that other objects throw a type-error
exception. Fix wrong references to iter-more under
documentation for iter-item.  Removed obsolete text specifying
that iter-step uses car on list-like sequences, a dubious
behavior removed in the previous commit.

1 files changed, 1 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index 9fcb98a6..cc4a21eb 100644
--- a/eval.c
+++ b/eval.c
@@ -7854,6 +7854,7 @@ void eval_init(void)
   reg_fun(intern(lit("iter-item"), user_package), func_n1(iter_item));
   reg_fun(intern(lit("iter-step"), user_package), func_n1(iter_step));
   reg_fun(intern(lit("iter-reset"), user_package), func_n2(iter_reset));
+  reg_fun(intern(lit("iterp"), user_package), func_n1(iterp));
   reg_fun(intern(lit("iter-cat"), user_package), func_n0v(iter_catv));
   reg_fun(intern(lit("copy-iter"), user_package), func_n1(copy_iter));