Compare sample implementation and Taylan's.

Author: arthurgleckler

contrib/README.org

@@ -1,2 +1,15 @@
 This directory contains implementations of SRFI 64 provided by people
-other than Per Bothner, the author of the SRFI.
+other than Per Bothner, the author of the SRFI.
+
+There are some differences between Per's sample implementation and
+Taylan's implementation:
+
+Per describes one advantage of his sample implementation:
+
+#+BEGIN_QUOTE
+One advantage of the reference implementation is that it has hooks for
+reporting line numbers for failing tests.  That seems impossibly to do
+portably, and difficult to do without some kind of macro hooks.
+#+END_QUOTE
+
+Taylan's implementation is mostly pure R7RS.