* eval.c (eval_init): lazy-str's third argument is optional.

Added lazy-stringp. Changing names of length-str-{gt,ge,lt,le}
to be consistent with the >, >=, < and <= functions.

* lib.c (lazy_stream_func): Greatly simplified implementation.
The lazy list now continues by means of recursing via
an optimized version of lazy_stream_cons called lazy_stream_cont.
The environment structure is simplified to just hold the next item,
rather than a pointless list. The pointless setting of lcons->lc.func
to nil is also removed; this is always done by the caller.
(lazy_stream_cont): New static function, similar to lazy_stream_cons,
but optimized by not consing up a new function and new environment
cell.
(lazy_stream_cons): The environment for the update function
is simplified to just a single cons.

* txr.1: Documented lazy string functions and lazy-stream-cons.

1 files changed, 6 insertions, 5 deletions

diff --git a/eval.c b/eval.c
index 501a20a0..77209599 100644
--- a/eval.c
+++ b/eval.c
@@ -2401,14 +2401,15 @@ void eval_init(void)
   reg_fun(intern(lit("break-str"), user_package), func_n2(break_str));
 
   reg_fun(intern(lit("lazy-stream-cons"), user_package), func_n1(lazy_stream_cons));
-  reg_fun(intern(lit("lazy-str"), user_package), func_n3(lazy_str));
+  reg_fun(intern(lit("lazy-str"), user_package), func_n3o(lazy_str, 1));
+  reg_fun(intern(lit("lazy-stringp"), user_package), func_n1(lazy_stringp));
   reg_fun(intern(lit("lazy-str-force-upto"), user_package), func_n2(lazy_str_force_upto));
   reg_fun(intern(lit("lazy-str-force"), user_package), func_n1(lazy_str_force));
   reg_fun(intern(lit("lazy-str-get-trailing-list"), user_package), func_n2(lazy_str_get_trailing_list));
-  reg_fun(intern(lit("length-str-gt"), user_package), func_n2(length_str_gt));
-  reg_fun(intern(lit("length-str-ge"), user_package), func_n2(length_str_ge));
-  reg_fun(intern(lit("length-str-lt"), user_package), func_n2(length_str_lt));
-  reg_fun(intern(lit("length-str-le"), user_package), func_n2(length_str_le));
+  reg_fun(intern(lit("length-str->"), user_package), func_n2(length_str_gt));
+  reg_fun(intern(lit("length-str->="), user_package), func_n2(length_str_ge));
+  reg_fun(intern(lit("length-str-<"), user_package), func_n2(length_str_lt));
+  reg_fun(intern(lit("length-str-<="), user_package), func_n2(length_str_le));
 
   reg_fun(intern(lit("vector"), user_package), func_n1(vector));
   reg_fun(intern(lit("vectorp"), user_package), func_n1(vectorp));