dis(): Not all opcodes are printable anymore, so print the repr

of the opcode character instead (but stripping the quotes).

Added a proto 2 test section for the canonical recursive-tuple case.
Note that since pickle's save_tuple() takes different paths depending on
tuple length now, beefier tests are really needed (but not in pickletools);
the "short tuple" case tried here was actually broken yesterday, and it's
subtle stuff so needs to be tested.

Lib/pickletools.py

@@ -1874,7 +1874,7 @@ def dis(pickle, out=None, indentlevel=4):
         if pos is not None:
             print >> out, "%5d:" % pos,
 
-        line = "%s %s%s" % (opcode.code,
+        line = "%-4s %s%s" % (repr(opcode.code)[1:-1],
                               indentchunk * len(markstack),
                               opcode.name)
 
@@ -2068,6 +2068,30 @@ pickle would require the disassembler to emulate the stack.
    11: 1        POP_MARK   (MARK at 0)
    12: h    BINGET     1
    14: .    STOP
+
+Try protocol 2.
+
+>>> dis(pickle.dumps(L, 2))
+    0: \x80 PROTO      2
+    2: ]    EMPTY_LIST
+    3: q    BINPUT     0
+    5: h    BINGET     0
+    7: \x85 TUPLE1
+    8: q    BINPUT     1
+   10: a    APPEND
+   11: .    STOP
+
+>>> dis(pickle.dumps(T, 2))
+    0: \x80 PROTO      2
+    2: ]    EMPTY_LIST
+    3: q    BINPUT     0
+    5: h    BINGET     0
+    7: \x85 TUPLE1
+    8: q    BINPUT     1
+   10: a    APPEND
+   11: 0    POP
+   12: h    BINGET     1
+   14: .    STOP
 """
 
 __test__ = {'disassembler_test': _dis_test,