my.reddit: refactor into module that supports pushshift/gdpr (#179)

* initial pushshift/rexport merge implementation, using id for merging
* smarter module deprecation warning using regex
* add `RedditBase` from promnesia
* `import_source` helper for gracefully handing mixin data sources

my/reddit/all.py

@@ -0,0 +1,68 @@
+from typing import Iterator
+from my.core.common import Stats
+from my.core.source import import_source
+
+from .common import Save, Upvote, Comment, Submission, _merge_comments
+
+# Man... ideally an all.py file isn't this verbose, but
+# reddit just feels like that much of a complicated source and
+# data acquired by different methods isn't the same
+
+### 'safe importers' -- falls back to empty data if the module couldn't be found
+rexport_src = import_source(module_name="my.reddit.rexport")
+pushshift_src = import_source(module_name="my.reddit.pushshift")
+
+@rexport_src
+def _rexport_comments() -> Iterator[Comment]:
+    from . import rexport
+    yield from rexport.comments()
+
+@rexport_src
+def _rexport_submissions() -> Iterator[Submission]:
+    from . import rexport
+    yield from rexport.submissions()
+
+@rexport_src
+def _rexport_saved() -> Iterator[Save]:
+    from . import rexport
+    yield from rexport.saved()
+
+@rexport_src
+def _rexport_upvoted() -> Iterator[Upvote]:
+    from . import rexport
+    yield from rexport.upvoted()
+
+@pushshift_src
+def _pushshift_comments() -> Iterator[Comment]:
+    from .pushshift import comments as pcomments
+    yield from pcomments()
+
+# Merged functions
+
+def comments() -> Iterator[Comment]:
+    # TODO: merge gdpr here
+    yield from _merge_comments(_rexport_comments(), _pushshift_comments())
+
+def submissions() -> Iterator[Submission]:
+    # TODO: merge gdpr here
+    yield from _rexport_submissions()
+
+@rexport_src
+def saved() -> Iterator[Save]:
+    from .rexport import saved
+    yield from saved()
+
+@rexport_src
+def upvoted() -> Iterator[Upvote]:
+    from .rexport import upvoted
+    yield from upvoted()
+
+def stats() -> Stats:
+    from my.core import stat
+    return {
+        **stat(saved),
+        **stat(comments),
+        **stat(submissions),
+        **stat(upvoted),
+    }
+