buf: new buffer stream.

* buf.c (struct buf_strm): New struct type.
(buf_strm_mark, int buf_strm_put_byte_callback,
buf_strm_put_string, buf_strm_put_char, buf_strm_put_byte,
buf_strm_get_byte_callback, buf_strm_get_char,
buf_strm_get_byte, buf_strm_unget_char, buf_strm_unget_byte,
buf_strm_seek, buf_strm_truncate, buf_strm_get_prop,
buf_strm_set_prop, buf_strm_get_error,
buf_strm_get_error_str): New static functions.
(buf_strm_ops): New static struct.
(buf_strm): New static function.
(make_buf_stream, get_buf_from_stream): New functions.
(buf_init): Register new intrinsic functiions make-buf-stream
and get-buf-from-stream.
Call fill_stream_ops on new buf_strm_ops to fill
default operations in place of function pointers
that have been left null.

* buf.h (make_buf_stream, get_buf_from_stream): Declared.

* lisplib.c (with_stream_set_entries): Add with-out-buf-stream
and with-in-buf-stream to auto-load symbols for with-stream.tl
module.

* share/txr/stdlib/with-stream.tl (with-out-buf-stream,
with-in-buf-stream): New macros.

* txr.1: New section about buffer streams.

1 files changed, 3 insertions, 0 deletions

diff --git a/buf.h b/buf.h
index f3ab4a7b..28978472 100644
--- a/buf.h
+++ b/buf.h
@@ -102,4 +102,7 @@ val buf_get_cptr(val buf, val pos);
 val buf_print(val buf, val stream);
 val buf_pprint(val buf, val stream);
 
+val make_buf_stream(val buf_opt);
+val get_buf_from_stream(val stream);
+
 void buf_init(void);