show off 'box' in the example

src/Example.hs

@@ -12,13 +12,21 @@ type Point
 op :: Record Point
 op = 0 & 0 & 0 & (0,0,0) & end
 
+type User
+  = '[ "nick"             := String
+     , "real name"        := String
+     , "gender"           := String
+     , "country of birth" := String ]
+
 main :: IO ()
 main = do
     point <- runcomp newIORef op
- -- point :: RecordT IORef Point
+    -- point :: RecordT IORef Point
 
-    let pointx = [get|x|] point
-        pointy = [get|x|] point
+    let pointx, pointy, pointz :: IORef Double
+        pointc :: IORef (Int, Int, Int)
+        pointx = [get|x|] point
+        pointy = [get|y|] point
         pointz = [get|z|] point
         pointc = [get|colour|] point
 
@@ -29,6 +37,22 @@ main = do
 
     -- "freeze" the record
     frozenPoint <- runtrans readIORef point
- -- frozenPoint :: Record Point
+    -- frozenPoint :: Record Point
     print frozenPoint
+    -- 0.0 & 1.0 & 2.0 & (255,255,0) & end
+
+    let greg :: Record User
+        greg = "GREG" & "Sir Greg of Gerg" & "Male" & "Gregland" & end
+
+        makeSpy :: Record User -> RecordT Maybe User
+        makeSpy = [set|real name|] Nothing . box Just
+
+    print greg
+    -- "GREG" & "Sir Greg of Gerg" & "Male" & "Gregland" & end
+
+    print (makeSpy greg)
+    -- Just "GREG" & Nothing & Just "Male" & Just "Gregland" & end
+
+    print (run (makeSpy greg))
+    -- Nothing