format: ~x/~X specifiers support buffers.

* buf.c (buf_hex): New function.

* buf.h (buf_hex): Declared.

* stream.c (formatv): Support printing of buffers in hex
via temporary buffer containing hex characters, similarly
to how bignums are handled.

* tests/018/format.tl: New file, providing some coverage over
new and affected code.

1 files changed, 2 insertions, 0 deletions

diff --git a/buf.h b/buf.h
index 1805f3b8..89c543e5 100644
--- a/buf.h
+++ b/buf.h
@@ -113,6 +113,8 @@ val buf_get_cptr(val buf, val pos);
 val buf_print(val buf, val stream);
 val buf_pprint(val buf, val stream);
 
+void buf_hex(val buf, char *, size_t, int);
+
 val make_buf_stream(val buf_opt);
 val get_buf_from_stream(val stream);