initial Buf docs

lib/Buf.pod

@@ -0,0 +1,31 @@
+=begin pod
+
+=head1 Buf
+
+    class Buf does Positional { ... }
+
+A C<Buf> (short for buffer) is a binary string, and generally returned from
+low-level IO operations. In the abstract it is just a list of integers, so
+for example indexing into a C<Buf> with C<.[$idx]> returns an C<Int>.
+
+=head2 Methods
+
+=head3 new
+
+    method new(*@codes)
+
+Creates a C<Buf> from a list of integers.
+
+=head3  Bool
+
+    multi method Bool(Buf:D:)
+
+Returns C<False> if and only if the buffer is empty.
+
+=head3 elems
+
+    multi method elems(Buf:D:) returns Int:D
+
+Returns the number of elements of the buffer.
+
+=end pod