Data commit

Task/Rendezvous/Python/rendezvous.py

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+"""An approximation of the rendezvous pattern found in Ada using asyncio."""
+from __future__ import annotations
+
+import asyncio
+import sys
+
+from typing import Optional
+from typing import TextIO
+
+
+class OutOfInkError(Exception):
+    """Exception raised when a printer is out of ink."""
+
+
+class Printer:
+    def __init__(self, name: str, backup: Optional[Printer]):
+        self.name = name
+        self.backup = backup
+
+        self.ink_level: int = 5
+        self.output_stream: TextIO = sys.stdout
+
+    async def print(self, msg):
+        if self.ink_level <= 0:
+            if self.backup:
+                await self.backup.print(msg)
+            else:
+                raise OutOfInkError(self.name)
+        else:
+            self.ink_level -= 1
+            self.output_stream.write(f"({self.name}): {msg}\n")
+
+
+async def main():
+    reserve = Printer("reserve", None)
+    main = Printer("main", reserve)
+
+    humpty_lines = [
+        "Humpty Dumpty sat on a wall.",
+        "Humpty Dumpty had a great fall.",
+        "All the king's horses and all the king's men,",
+        "Couldn't put Humpty together again.",
+    ]
+
+    goose_lines = [
+        "Old Mother Goose,",
+        "When she wanted to wander,",
+        "Would ride through the air,",
+        "On a very fine gander.",
+        "Jack's mother came in,",
+        "And caught the goose soon,",
+        "And mounting its back,",
+        "Flew up to the moon.",
+    ]
+
+    async def print_humpty():
+        for line in humpty_lines:
+            try:
+                task = asyncio.Task(main.print(line))
+                await task
+            except OutOfInkError:
+                print("\t Humpty Dumpty out of ink!")
+                break
+
+    async def print_goose():
+        for line in goose_lines:
+            try:
+                task = asyncio.Task(main.print(line))
+                await task
+            except OutOfInkError:
+                print("\t Mother Goose out of ink!")
+                break
+
+    await asyncio.gather(print_goose(), print_humpty())
+
+
+if __name__ == "__main__":
+    asyncio.run(main(), debug=True)