From 73bcd69a66e50e08bace63cc2392803fd991f6f0 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 27 Feb 2014 07:52:02 -0800
Subject: * lib.c (copy): New function.

* lib.h (copy): Declared.

* eval.c (eval_init): Registered copy function as intrinsic.

* txr.1: Added missing documentation for length. Documented copy.
---
 ChangeLog | 10 ++++++++++
 eval.c    |  2 +-
 lib.c     | 18 ++++++++++++++++++
 lib.h     |  1 +
 txr.1     | 28 +++++++++++++++++++++++++++-
 5 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 80739b7a..f2df059a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2014-02-27  Kaz Kylheku  <kaz@kylheku.com>
+
+	* lib.c (copy): New function.
+
+	* lib.h (copy): Declared.
+
+	* eval.c (eval_init): Registered copy function as intrinsic.
+
+	* txr.1: Added missing documentation for length. Documented copy.
+
 2014-02-27  Kaz Kylheku  <kaz@kylheku.com>
 
 	* genvim.txr: Updated with regard to how operators are registered in
diff --git a/eval.c b/eval.c
index a1566c4c..9cb75aa7 100644
--- a/eval.c
+++ b/eval.c
@@ -3483,7 +3483,7 @@ void eval_init(void)
   reg_fun(intern(lit("set-diff"), user_package), func_n4o(set_diff, 2));
 
   reg_fun(intern(lit("length"), user_package), func_n1(length));
-
+  reg_fun(intern(lit("copy"), user_package), func_n1(copy));
   reg_fun(intern(lit("sub"), user_package), func_n3o(sub, 1));
   reg_fun(intern(lit("ref"), user_package), func_n2(ref));
   reg_fun(intern(lit("refset"), user_package), func_n3(refset));
diff --git a/lib.c b/lib.c
index 9aa3af95..da3ae5a3 100644
--- a/lib.c
+++ b/lib.c
@@ -4879,6 +4879,24 @@ val set_diff(val list1, val list2, val testfun, val keyfun)
   return make_like(out, list_orig);
 }
 
+val copy(val seq)
+{
+  switch (type(seq)) {
+  case NIL:
+    return nil;
+  case CONS:
+  case LCONS:
+    return copy_list(seq);
+  case LIT:
+  case STR:
+    return copy_str(seq);
+  case VEC:
+    return copy_vec(seq);
+  default:
+    type_mismatch(lit("copy: ~s is not a sequence"), seq, nao);
+  }
+}
+
 val length(val seq)
 {
   switch (type(seq)) {
diff --git a/lib.h b/lib.h
index d3f251fc..d2548e09 100644
--- a/lib.h
+++ b/lib.h
@@ -687,6 +687,7 @@ val posq(val obj, val list);
 val pos(val list, val key, val testfun, val keyfun);
 val pos_if(val pred, val list, val key);
 val set_diff(val list1, val list2, val testfun, val keyfun);
+val copy(val seq);
 val length(val seq);
 val sub(val seq, val from, val to);
 val ref(val seq, val ind);
diff --git a/txr.1 b/txr.1
index 1aa82bb6..243e0c93 100644
--- a/txr.1
+++ b/txr.1
@@ -9355,10 +9355,36 @@ produces a catenation of the vectors listed in <vec-list>. It returns
 a single large vector formed by catenating those vectors together in
 order.
 
-.SH GENERIC SEQUENCE OPERATIONS
+.SH SEQUENCE MANIPULATION
 
 .SS Function length
 
+.TP
+Syntax:
+
+  (length <sequence>)
+
+.TP
+Description:
+
+The length function returns the number of items in <sequence>, and
+returns it.
+
+.SS Function copy
+
+.TP
+Syntax:
+
+  (copy <sequence>)
+
+.TP
+Description:
+
+The copy function duplicates a sequence. If <sequence> is nil, it
+returns nil. If <sequence> is a list, it returns (copy-list <sequence>);
+if <sequence> is a string, it returns (copy-str <sequence>); and
+if <sequence> is a vector, it returns (copy-vec <sequence>).
+
 .SS Function sub
 
 .TP
-- 
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