mention pure output predicates in the README

diff --git a/README.md b/README.md
index 8da7f4d3f39665c1448a8e5c75d9a9f52b220655..37405b45075844713c8f8257c17b7c9aa717166c 100644 (file)
--- a/README.md
+++ b/README.md
@@ -464,6 +464,8 @@ The modules that ship with Scryer Prolog are also called
   file, reading lazily only as much as is needed. Due to the compact
   internal string representation, also extremely large files can be
   efficiently processed with Scryer Prolog in this way.
+  `phrase_to_file/2` and `phrase_to_stream/2` write lists of
+  characters described by DCGs to files and streams, respectively.
 * [`lambda`](src/lib/lambda.pl)
   Lambda expressions to simplify higher order programming.
 * [`charsio`](src/lib/charsio.pl) Various predicates that are useful