Merge pull request #310 from chrrasmussen/replace-ffi-in-hex-function

Replace FFI implementation of 'hex' function with a plain Idris version

src/Compiler/Scheme/Racket.idr

@@ -56,14 +56,8 @@ showRacketChar : Char -> String -> String
 showRacketChar '\\' = ("\\\\" ++)
 showRacketChar c
    = if c < chr 32 || c > chr 126
-        then (("\\u" ++ pad (asHex (cast c))) ++)
+        then (("\\u" ++ leftPad '0' 4 (asHex (cast c))) ++)
         else strCons c
-  where
-    pad : String -> String
-    pad str
-        = case isLTE (length str) 4 of
-               Yes _ => pack (List.replicate (minus 4 (length str)) '0') ++ str
-               No _ => str
 
 showRacketString : List Char -> String -> String
 showRacketString [] = id

src/Idris/IDEMode/Commands.idr

@@ -3,6 +3,7 @@ module Idris.IDEMode.Commands
 import Core.Core
 import Core.Name
 import public Idris.REPLOpts
+import Utils.Hex
 
 import System.File
 
@@ -253,21 +254,14 @@ export
 version : Int -> Int -> SExp
 version maj min = toSExp (SymbolAtom "protocol-version", maj, min)
 
-%foreign "C:fprintf,libc 6"
-prim__printfHex : AnyPtr -> String -> Int -> PrimIO ()
-
-hex : File -> Int -> IO ()
-hex (FHandle h) num
-    = primIO $ prim__printfHex h "%06x" num
-
-sendLine : File -> String -> IO ()
-sendLine f st =
+sendStr : File -> String -> IO ()
+sendStr f st =
   map (const ()) (fPutStr f st)
 
 export
 send : SExpable a => File -> a -> Core ()
 send f resp
     = do let r = show (toSExp resp) ++ "\n"
-         coreLift $ hex f (cast (length r))
-         coreLift $ sendLine f r
+         coreLift $ sendStr f $ leftPad '0' 6 (asHex (cast (length r)))
+         coreLift $ sendStr f r
          coreLift $ fflush f

src/Utils/Hex.idr

@@ -1,5 +1,6 @@
 module Utils.Hex
 
+import Data.List
 import Data.Primitives.Views
 
 %default total
@@ -26,13 +27,23 @@ hexDigit _ = 'X' -- TMP HACK: Ideally we'd have a bounds proof, generated below
 ||| Convert a positive integer into a list of (lower case) hexadecimal characters
 export
 asHex : Int -> String
-asHex n = pack $ asHex' n []
+asHex n =
+  if n > 0
+    then pack $ asHex' n []
+    else "0"
   where
     asHex' : Int -> List Char -> List Char
     asHex' 0 hex = hex
     asHex' n hex with (n `divides` 16)
       asHex' (16 * div + rem) hex | DivBy div rem _ =
-        assert_total $ asHex' div (hexDigit rem :: hex)
+        asHex' (assert_smaller n div) (hexDigit rem :: hex)
+
+export
+leftPad : Char -> Nat -> String -> String
+leftPad paddingChar padToLength str =
+  if length str < padToLength
+    then pack (List.replicate (minus padToLength (length str)) paddingChar) ++ str
+    else str
 
 export
 fromHexDigit : Char -> Maybe Int