Make Human work w/ both prompt_toolkit v1 and v2

As of today, some systems work with prompt_toolkit v1 by default, but
Arch Linux has migrated to v2, and it's the last version on PyPI

To maintain the Arch Linux package of this library, it was required to
revert the 8dba4c0 commit, yet that didn't suffice to make the Human
class work in that system

This commit changes the Human strategy to work on environments with
either prompt_toolkit versions, the main differences are:

- Human._history_toolbar no longer return a list with a tuple, but
  just the raw content (making its tests more straightforward)
- self.status_messages["toolbar"] is a function as expected by the
  prompt_toolkit version available

Although the "pygments.toolbar" string is there when using the
prompt_toolkit v2, the "pygments" library isn't a dependency, since
using the Human strategy works fine in a virtual environment without
pygments

Author: danilobellini

axelrod/strategies/human.py

@@ -3,13 +3,27 @@
 from axelrod.action import Action
 from axelrod.player import Player
 from prompt_toolkit import prompt
-from prompt_toolkit.styles import style_from_dict
-from prompt_toolkit.token import Token
 from prompt_toolkit.validation import ValidationError, Validator
 
+try:  # prompt_toolkit v1
+    from prompt_toolkit.styles import style_from_dict
+    from prompt_toolkit.token import Token
+
+    token_toolbar = Token.Toolbar
+    bottom_toolbar_name = "get_bottom_toolbar_tokens"
+    PROMPT2 = False
+
+except ImportError:  # prompt_toolkit v2
+    from prompt_toolkit.styles import Style
+
+    style_from_dict = Style.from_dict
+    token_toolbar = "pygments.toolbar"
+    bottom_toolbar_name = "bottom_toolbar"
+    PROMPT2 = True
+
 C, D = Action.C, Action.D
 
-toolbar_style = style_from_dict({Token.Toolbar: "#ffffff bg:#333333"})
+toolbar_style = style_from_dict({token_toolbar: "#ffffff bg:#333333"})
 
 
 class ActionValidator(Validator):
@@ -65,7 +79,7 @@ def __init__(self, name="human", c_symbol="C", d_symbol="D"):
         self.symbols = {C: c_symbol, D: d_symbol}
         self.opponent_history = []
 
-    def _history_toolbar(self, cli):
+    def _history_toolbar(self):
         """
         A prompt-toolkit function to define the bottom toolbar.
         Described at http://python-prompt-toolkit.readthedocs.io/en/latest/pages/building_prompts.html#adding-a-bottom-toolbar
@@ -77,7 +91,7 @@ def _history_toolbar(self, cli):
             content = "History ({}, opponent): {}".format(self.human_name, history)
         else:
             content = ""
-        return [(Token.Toolbar, content)]
+        return content
 
     def _status_messages(self):
         """
@@ -95,7 +109,11 @@ def _status_messages(self):
             mapping print or toolbar to the relevant string
         """
         if self.history:
-            toolbar = self._history_toolbar
+            toolbar = (
+                self._history_toolbar
+                if PROMPT2
+                else lambda cli: [(token_toolbar, self._history_toolbar())]
+            )
             print_statement = "{}Turn {}: {} played {}, opponent played {}".format(
                 linesep,
                 len(self.history),
@@ -124,8 +142,8 @@ def _get_human_input(self) -> Action:  # pragma: no cover
                 len(self.history) + 1, self.human_name
             ),
             validator=ActionValidator(),
-            get_bottom_toolbar_tokens=self.status_messages["toolbar"],
             style=toolbar_style,
+            **{bottom_toolbar_name: self.status_messages["toolbar"]},
         )
 
         return Action.from_char(action.upper())

axelrod/tests/strategies/test_human.py

@@ -52,13 +52,13 @@ def test_init(self):
     def test_history_toolbar(self):
         human = Human()
         expected_content = ""
-        actual_content = human._history_toolbar(None)[0][1]
+        actual_content = human._history_toolbar()
         self.assertEqual(actual_content, expected_content)
 
         human.history = [C]
         human.opponent_history = [C]
         expected_content = "History (human, opponent): [('C', 'C')]"
-        actual_content = human._history_toolbar(None)[0][1]
+        actual_content = human._history_toolbar()
         self.assertIn(actual_content, expected_content)
 
     def test_status_messages(self):

requirements.txt

@@ -4,7 +4,7 @@ hypothesis==3.2
 matplotlib>=2.0.0,<3.0.0
 numpy>=1.9.2
 pandas>=0.18.1
-prompt-toolkit>=1.0.7,<2.0.0
+prompt-toolkit>=1.0.7
 scipy>=0.19.0
 toolz>=0.8.0
 tqdm>=3.4.0