1 files changed, 76 insertions, 0 deletions
diff --git a/examples/statemachine/vending_machine.py b/examples/statemachine/vending_machine.py
new file mode 100644
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+++ b/examples/statemachine/vending_machine.py
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+#
+# vending_machine.py
+#
+# Example of using the statemachine parser without importing a .pystate module.
+#
+# A vending machine that
+
+import statemachine
+
+# Vending machine buttons:
+#    A, B, C, D
+#    1, 2, 3, 4
+#
+vending_machine_state_description = """\
+statemachine VendingMachineState:
+    Idle-(press_alpha_button)->WaitingOnDigit
+    WaitingOnDigit-(press_alpha_button)->WaitingOnDigit
+    WaitingOnDigit-(press_digit_button)->DispenseProduct
+    DispenseProduct-(dispense)->Idle
+"""
+
+# convert state machine text to state classes
+generated = statemachine.namedStateMachine.transformString(vending_machine_state_description)
+# print(generated)
+# exec generated code to define state classes and state mixin
+exec(generated)
+
+class VendingMachine(VendingMachineStateMixin):
+    def __init__(self):
+        self.initialize_state(Idle)
+        self._pressed = None
+        self._alpha_pressed = None
+        self._digit_pressed = None
+
+    def press_button(self, button):
+        if button in "ABCD":
+            self._pressed = button
+            self.press_alpha_button()
+        elif button in "1234":
+            self._pressed = button
+            self.press_digit_button()
+        else:
+            print('Did not recognize button {!r}'.format(str(button)))
+
+    def press_alpha_button(self):
+        try:
+            super(VendingMachine, self).press_alpha_button()
+        except VendingMachineState.InvalidTransitionException as ite:
+            print(ite)
+        else:
+            self._alpha_pressed = self._pressed
+
+    def press_digit_button(self):
+        try:
+            super(VendingMachine, self).press_digit_button()
+        except VendingMachineState.InvalidTransitionException as ite:
+            print(ite)
+        else:
+            self._digit_pressed = self._pressed
+            self.dispense()
+
+    def dispense(self):
+        try:
+            super(VendingMachine, self).dispense()
+        except VendingMachineState.InvalidTransitionException as ite:
+            print(ite)
+        else:
+            print("Dispensing at {}{}".format(self._alpha_pressed, self._digit_pressed))
+            self._alpha_pressed = self._digit_pressed = None
+
+
+vm = VendingMachine()
+for button in "1 A B 1".split():
+    print(">> pressing {!r}".format(button))
+    vm.press_button(button)
+    print("Vending machine is now in {} state".format(vm.state))