update from Atlas with major reorg

attic/concurrency/spinner_asyncio.py

@@ -0,0 +1,42 @@
+# spinner_asyncio.py
+
+# credits: Example by Luciano Ramalho inspired by
+# Michele Simionato's multiprocessing example
+# source:
+# http://python-3-patterns-idioms-test.readthedocs.org/en/latest/CoroutinesAndConcurrency.html
+
+import sys
+import asyncio
+
+DELAY = 0.1
+DISPLAY = '|/-\\'
+
+@asyncio.coroutine
+def spinner_func(before='', after=''):
+    write, flush = sys.stdout.write, sys.stdout.flush
+    while True:
+        for char in DISPLAY:
+            msg = '{} {} {}'.format(before, char, after)
+            write(msg)
+            flush()
+            write('\x08' * len(msg))
+            try:
+                yield from asyncio.sleep(DELAY)
+            except asyncio.CancelledError:
+                return
+
+
+@asyncio.coroutine
+def long_computation(delay):
+    # emulate a long computation
+    yield from asyncio.sleep(delay)
+
+
+if __name__ == '__main__':
+    loop = asyncio.get_event_loop()
+    spinner = loop.create_task(spinner_func('Please wait...', 'thinking!'))
+    long_task = loop.create_task(long_computation(3))
+    long_task.add_done_callback(lambda f: spinner.cancel())
+    loop.run_until_complete(spinner)
+    loop.close()
+