Switch to using %r in the format string.

Parser/asdl.py

@@ -98,7 +98,7 @@ class ASDLScanner(spark.GenericScanner, object):
 
     def t_default(self, s):
         r" . +"
-        raise ValueError, "unmatched input: %s" % repr(s)
+        raise ValueError, "unmatched input: %r" % s
 
 class ASDLParser(spark.GenericParser, object):
     def __init__(self):

Parser/asdl_c.py

@@ -47,7 +47,7 @@ def reflow_lines(s, depth):
         # XXX this should be fixed for real
         if i == -1 and 'GeneratorExp' in cur:
             i = size + 3
-        assert i != -1, "Impossible line %d to reflow: %s" % (size, repr(s))
+        assert i != -1, "Impossible line %d to reflow: %r" % (size, s)
         lines.append(padding + cur[:i])
         if len(lines) == 1:
             # find new size based on brace