Source code for axelrod.strategies.handshake
from typing import List
from axelrod.action import Action
from axelrod.player import Player
C, D = Action.C, Action.D
[docs]
class Handshake(Player):
"""Starts with C, D. If the opponent plays the same way, cooperate forever,
else defect forever.
Names:
- Handshake: [Robson1990]_
"""
name = "Handshake"
classifier = {
"memory_depth": float("inf"), # Long memory
"stochastic": False,
"long_run_time": False,
"inspects_source": False,
"manipulates_source": False,
"manipulates_state": False,
}
def __init__(self, initial_plays: List[Action] = None) -> None:
super().__init__()
if not initial_plays:
initial_plays = [C, D]
self.initial_plays = initial_plays
[docs]
def strategy(self, opponent: Player) -> Action:
"""Actual strategy definition that determines player's action."""
# Begin by playing the sequence C, D
index = len(self.history)
if index < len(self.initial_plays):
return self.initial_plays[index]
# If our opponent played [C, D] on the first two moves, cooperate
# forever. Otherwise defect forever.
if opponent.history[0 : len(self.initial_plays)] == self.initial_plays:
return C
return D