fixing CSV exporter

Author: mmatera

mathics/autoload/formats/CSV/Export.m

@@ -22,7 +22,7 @@
     FunctionChannels -> {"Streams"},
     Options -> {"ByteOrderMark"},
     DefaultElement -> "Plaintext",
-    BinaryFormat -> True,
+    BinaryFormat -> False,
     Options -> {
         "CharacterEncoding",
         "FieldSeparators"

mathics/builtin/files.py

@@ -20,6 +20,7 @@
 import requests
 import pathlib
 
+from io import BytesIO, StringIO
 import os.path as osp
 from itertools import chain
 
@@ -1959,8 +1960,10 @@ def apply(self, channel, expr, evaluation):
                     Expression("FullForm", result).evaluate(evaluation),
                 )
             exprs.append(result)
-
-        stream.write("".join(exprs))
+        line = "".join(exprs)
+        if type(stream) is BytesIO:
+            line = line.encode('utf8')
+        stream.write(line)
         try:
             stream.flush()
         except IOError as err:

mathics/builtin/lists.py

@@ -188,7 +188,7 @@ class ByteArray(Builtin):
     </dl>
 
     >> A=ByteArray[{1,25,3}]
-     = ByteArray["AQID"]
+     = ByteArray["ARkD"]
     >> A[[2]]
      = 25
     >> B=ByteArray["asy"]