string/nat lit stuff

lib/Quox/Untyped/Scheme.idr

@@ -7,6 +7,7 @@ import Quox.Pretty
 
 import Quox.EffExtra
 import Quox.CharExtra
+import Quox.NatExtra
 import Data.DPair
 import Data.List1
 import Data.String
@@ -278,28 +279,16 @@ prelude = """
 ;;;;;;
 """
 
-export
-toHex : Int -> String
-toHex x =
-  case toHex' x of
-    [<] => "0"
-    cs  => concatMap singleton cs
-where
-  toHex' : Int -> SnocList Char
-  toHex' x =
-    if x == 0 then [<] else
-    let d = x `div` 16
-        m = x `mod` 16 in
-    toHex' (assert_smaller x d) :<
-    assert_total strIndex "0123456789abcdef" m
-
 export
 escape : String -> String
-escape = concatMap esc1 . unpack where
+escape = foldMap esc1 . unpack where
   esc1 : Char -> String
-  esc1 c = if c < ' ' || c > '~' || c == '\\' || c == '"'
-              then "\\x" ++ toHex (ord c) ++ ";"
-              else singleton c
+  esc1 c =
+    if c == '\\' || c == '"' then
+      "\\" ++ singleton c
+    else if c < ' ' || c > '~' then
+      "\\x" ++ showHex (ord c) ++ ";"
+    else singleton c
 
 export covering
 defToScheme : Name -> Definition -> Eff Scheme (Maybe Sexp)