A bit of library clean-up

lib/io.tri

@@ -91,8 +91,8 @@ onResult_ = action errCase okCase :
 -- Convenience helpers
 -- ---------------------------------------------------------------------------
 
-print    = s : bind (putStr s)       (_ : pure t)
-putStrLn = s : bind (putStr (append s "\n")) (_ : pure t)
+print    = s : void (putStr s)
+putStrLn = s : void (putStr (append s "\n"))
 
 -- ---------------------------------------------------------------------------
 -- Result-aware file helpers
@@ -117,18 +117,12 @@ writeFileOrPrintError = (path contents okCase :
     okCase)
 
 copyFile = (src dst :
-  bind (readFile src)
-    (result :
-      matchResult
-        (err rest : putStrLn (append "Read failed: " err))
-        (contents rest :
-          bind (writeFile dst contents)
-            (wr :
-              matchResult
-                (err rest : putStrLn (append "Write failed: " err))
-                (ok rest   : pure t)
-                wr))
-        result))
+  onResult (readFile src)
+    (err rest : putStrLn (append "Read failed: " err))
+    (contents rest :
+      onResult (writeFile dst contents)
+        (err rest : putStrLn (append "Write failed: " err))
+        (_ _ : pure t)))
 
 -- ---------------------------------------------------------------------------
 -- Resource-safe combinators