From 867162ac77d5e35ded33a44578d6ef0eeb16cd49 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 28 Jun 2020 08:48:20 -0700
Subject: New functions: list-seq, ved-seq and str-seq.

These functions convert any iterable to a list, vector or
string.

* eval.c (eval_init): Registered list-seq, vec-seq and str-seq
intrinsics.

* lib.c (list_seq, vec_seq, str_seq): New functions.

* lib.h (list_seq, vec_seq, str_seq): Declared.

* txr.1: Documented.
---
 eval.c |  3 +++
 lib.c  | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 lib.h  |  3 +++
 txr.1  | 29 +++++++++++++++++++++++++++++
 4 files changed, 81 insertions(+)

diff --git a/eval.c b/eval.c
index 405851f1..cd282da0 100644
--- a/eval.c
+++ b/eval.c
@@ -6926,6 +6926,9 @@ void eval_init(void)
   reg_fun(intern(lit("uni"), user_package), func_n4o(uni, 2));
 
   reg_fun(intern(lit("seqp"), user_package), func_n1(seqp));
+  reg_fun(intern(lit("list-seq"), user_package), func_n1(list_seq));
+  reg_fun(intern(lit("vec-seq"), user_package), func_n1(vec_seq));
+  reg_fun(intern(lit("str-seq"), user_package), func_n1(str_seq));
   reg_fun(intern(lit("length"), user_package), length_f);
   reg_fun(intern(lit("len"), user_package), length_f);
   reg_fun(intern(lit("empty"), user_package), func_n1(empty));
diff --git a/lib.c b/lib.c
index c2180abb..040294b5 100644
--- a/lib.c
+++ b/lib.c
@@ -1486,6 +1486,52 @@ val seqp(val obj)
   return tnil(si.kind != SEQ_NOTSEQ);
 }
 
+val list_seq(val seq)
+{
+  val self = lit("list-seq");
+  seq_iter_t iter;
+  val elem;
+  seq_iter_init(self, &iter, seq);
+  list_collect_decl (out, ptail);
+
+  while (seq_get(&iter, &elem))
+    ptail = list_collect(ptail, elem);
+
+  return out;
+}
+
+val vec_seq(val seq)
+{
+  val self = lit("vec-seq");
+  seq_iter_t iter;
+  val elem;
+  val vec = vector(zero, nil);
+  seq_iter_init(self, &iter, seq);
+
+  while (seq_get(&iter, &elem))
+    vec_push(vec, elem);
+
+  return vec;
+}
+
+val str_seq(val seq)
+{
+  val self = lit("str-seq");
+  seq_iter_t iter;
+  val elem;
+  val str = mkustring(zero);
+  seq_iter_init(self, &iter, seq);
+
+  while (seq_get(&iter, &elem)) {
+    if (chrp(elem) || stringp(elem))
+      string_extend(str, elem);
+    else
+      unsup_obj(self, elem);
+  }
+
+  return str;
+}
+
 loc list_collect(loc ptail, val obj)
 {
   val items = cons(obj, nil);
diff --git a/lib.h b/lib.h
index dff5f178..3e97d45d 100644
--- a/lib.h
+++ b/lib.h
@@ -620,6 +620,9 @@ val tolist(val seq);
 val nullify(val obj);
 val empty(val seq);
 val seqp(val obj);
+val list_seq(val seq);
+val vec_seq(val seq);
+val str_seq(val seq);
 val nreverse(val in);
 val reverse(val in);
 val us_nreverse(val in);
diff --git a/txr.1 b/txr.1
index 84b1dab7..c81b4523 100644
--- a/txr.1
+++ b/txr.1
@@ -29227,6 +29227,35 @@ then convert the resulting list to the same type as an input value
 by using
 .codn make-like .
 
+.coNP Functions @, list-seq @ vec-seq and @ str-seq
+.synb
+.mets (list-seq << iterable )
+.mets (vec-seq << iterable )
+.mets (str-seq << iterable )
+.syne
+.desc
+The
+.codn list-seq ,
+.code vec-seq
+and
+.code str-seq
+functions convert an iterable object of any type into a list, vector
+or string, respectively.
+
+The
+.code list-seq
+and
+.code vec-seq
+iterate the items of
+.meta iterable
+and accumulate these items into a new list or vector.
+
+The
+.code str-seq
+similarly iterates the items of
+.metn iterable ,
+requiring them to be a mixture of characters and strings.
+
 .coNP Functions @ length and @ len
 .synb
 .mets (length << iterable )
-- 
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