Nested expressions

1 files changed, 9 insertions, 0 deletions

diff --git a/common.sml b/common.sml
index 02c3724..e947e0f 100644
--- a/common.sml
+++ b/common.sml
@@ -134,6 +134,15 @@ in
   fun printf g = Fold.fold ctx g
 end
 
+fun sprintf g =
+let
+  val buf = ref []
+  fun output s = buf := s :: !buf
+  fun finish _ = String.concat $ rev $ !buf
+in
+  Fold.fold ((false, makePrintfBase output), finish)
+end g
+
 fun Printf out g = Fold.fold ((false, out), fn _ => ()) g
 
 local