Fixed examples. They didn't work with python3

examples/calc.py

@@ -22,7 +22,7 @@ calc_grammar = """
 """
 
 class CalculateTree(InlineTransformer):
-    from operator import add, sub, mul, div, neg
+    from operator import add, sub, mul, truediv as div, neg
     number = float
 
     def __init__(self):
@@ -50,8 +50,8 @@ def main():
 
 def test():
     # print calc("a=(1+2)")
-    print calc("a = 1+2")
-    print calc("1+a*-3")
+    print(calc("a = 1+2"))
+    print(calc("1+a*-3"))
 
 if __name__ == '__main__':
     test()

examples/indented_tree.py

@@ -7,15 +7,17 @@ It is crucial for the indenter that the NL_type matches the spaces (and tabs) af
 from lark.lark import Lark
 from lark.indenter import Indenter
 
-tree_grammar = """
+tree_grammar = r"""
     ?start: _NL* tree
 
-    tree: /\w+/ _NL [_INDENT tree+ _DEDENT]
+    tree: NAME _NL [_INDENT tree+ _DEDENT]
 
     NAME: /\w+/
 
     WS.ignore: /\s+/
-    _NL.newline: /(\r?\n[\t ]*)+/
+    _NL: /(\r?\n[\t ]*)+/
+    _INDENT: "<INDENT>"
+    _DEDENT: "<DEDENT>"
 """
 
 class TreeIndenter(Indenter):
@@ -39,7 +41,7 @@ a
 """
 
 def test():
-    print parser.parse(test_tree).pretty()
+    print(parser.parse(test_tree).pretty())
 
 if __name__ == '__main__':
     test()

examples/json_parser.py

@@ -53,12 +53,12 @@ def test():
     '''
 
     j = parse(test_json)
-    print j
+    print(j)
     import json
     assert j == json.loads(test_json)
 
 if __name__ == '__main__':
     test()
     with open(sys.argv[1]) as f:
-        print parse(f.read())
+        print(parse(f.read()))