From f301e8071b32552f8096286ae7c978ab9e79061c Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sat, 15 Jun 2019 21:48:49 -0700
Subject: buffers: expose sub-buf and replace-buf.

* buf.c (buf_init): Intrinsics sub-buf and replace-buf
registered.

* txr.1: Documented.
---
 buf.c |  2 ++
 txr.1 | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/buf.c b/buf.c
index 506ac45a..910d7801 100644
--- a/buf.c
+++ b/buf.c
@@ -1075,6 +1075,8 @@ void buf_init(void)
   reg_fun(intern(lit("length-buf"), user_package), func_n1(length_buf));
   reg_fun(intern(lit("buf-alloc-size"), user_package), func_n1(buf_alloc_size));
   reg_fun(intern(lit("copy-buf"), user_package), func_n1(copy_buf));
+  reg_fun(intern(lit("sub-buf"), user_package), func_n3(sub_buf));
+  reg_fun(intern(lit("replace-buf"), user_package), func_n4(replace_buf));
 
 #if HAVE_I8
   reg_fun(intern(lit("buf-put-i8"), user_package), func_n3(buf_put_i8));
diff --git a/txr.1 b/txr.1
index 72cbdbce..635ce352 100644
--- a/txr.1
+++ b/txr.1
@@ -26871,6 +26871,13 @@ is a
 object, then the function behaves like
 .codn carray-sub .
 
+If
+.meta sequence
+is a
+.code buf
+object, then the function behaves like
+.codn buf-sub .
+
 If
 .meta sequence
 is a structure, it must support the
@@ -27049,6 +27056,15 @@ object, then
 behaves like
 .codn carray-replace .
 
+If
+.meta sequence
+is a
+.code buf
+object, then
+.code replace
+behaves like
+.codn buf-replace .
+
 If
 .meta sequence
 is a structure, then the structure must support the
@@ -59542,6 +59558,49 @@ which has the same length and contents, and compares
 to
 .metn buf .
 
+.coNP Function @ sub-buf
+.synb
+.mets (sub-buf < buf >> [ from <> [ to ]])
+.syne
+.desc
+The
+.code sub-buf
+function has the same semantics as the
+.code sub
+function, except that the first argument must be a buffer.
+
+The extracted sub-range of a buffer is itself a buffer object.
+
+For a description of the arguments and semantics, refer to the
+.code sub
+function.
+
+.coNP Function @ replace-buf
+.synb
+.mets (replace-buf < buf < item-sequence >> [ from <> [ to ]])
+.syne
+.desc
+The
+.code replace-buf
+function has the same semantics as the
+.code replace
+function, except that the first argument must be a buffer.
+
+The elements of
+.code item-sequence
+are stored into
+.meta buf
+as if using the
+.code buf-put-u8
+function and therefore must be suitable
+.meta val
+arguments for that function.
+
+The of the arguments, semantics and return value given for
+.code replace
+apply to
+.codn replace-buf .
+
 .coNP Function @ buf-put-i8
 .synb
 .mets (buf-put-i8 < buf < pos << val )
-- 
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