BLD: consolidate remaining extensions

moves extensions to pandas/_libs, which holds the extension code
and also the generated builds (as its importable).

pandas/_libs/src is now almost an includes dir, holding low-frequency changing code.
This consolidates the import process making it more uniform and
consistent throughout the codebase.

Finally this cleans up the remaining top-level namespace (with some deprecations in place for
example pandas.lib, pandas.tslib, pandas.json, pandas.parser.

I listed all of the changes in the whatsnew, but I
don't think worthwhile deprecating anything else.

Author: Jeff Reback <jeff@reback.net>

Closes #15537 from jreback/extensions3 and squashes the following commits:

a6d6cfa [Jeff Reback] BLD: rename / move some extensions

Author: jreback

Makefile

@@ -1,4 +1,4 @@
-tseries: pandas/lib.pyx pandas/tslib.pyx pandas/hashtable.pyx
+tseries: pandas/_libs/lib.pyx pandas/_libs/tslib.pyx pandas/_libs/hashtable.pyx
 	python setup.py build_ext --inplace
 
 .PHONY : develop build clean clean_pyc tseries doc

asv_bench/benchmarks/binary_ops.py

@@ -107,4 +107,4 @@ def setup(self):
         self.s = Series(date_range('20010101', periods=self.N, freq='T', tz='US/Eastern'))
         self.ts = self.s[self.halfway]
 
-        self.s2 = Series(date_range('20010101', periods=self.N, freq='s',  tz='US/Eastern'))
+        self.s2 = Series(date_range('20010101', periods=self.N, freq='s',  tz='US/Eastern'))

asv_bench/benchmarks/pandas_vb_common.py

@@ -8,16 +8,22 @@
 import random
 import numpy as np
 import threading
+from importlib import import_module
+
 try:
     from pandas.compat import range
 except ImportError:
     pass
 
 np.random.seed(1234)
-try:
-    import pandas._tseries as lib
-except:
-    import pandas.lib as lib
+
+# try em until it works!
+for imp in ['pandas_tseries', 'pandas.lib', 'pandas._libs.lib']:
+    try:
+        lib = import_module(imp)
+        break
+    except:
+        pass
 
 try:
     Panel = Panel

asv_bench/benchmarks/panel_methods.py

@@ -21,4 +21,4 @@ def time_shift(self):
         self.panel.shift(1)
 
     def time_shift_minor(self):
-        self.panel.shift(1, axis='minor')
+        self.panel.shift(1, axis='minor')

doc/source/whatsnew/v0.20.0.txt

@@ -484,6 +484,35 @@ New Behavior:
    In [11]: index.memory_usage(deep=True)
    Out[11]: 260
 
+.. _whatsnew_0200.api_breaking.extensions:
+
+Extension Modules Moved
+^^^^^^^^^^^^^^^^^^^^^^^
+
+Some formerly public c/c++/cython extension modules have been moved and/or renamed. These are all removed from the public API.
+If indicated, a deprecation warning will be issued if you reference that module. (:issue:`12588`)
+
+.. csv-table::
+    :header: "Previous Location", "New Location", "Deprecated"
+    :widths: 30, 30, 4
+
+    "pandas.lib", "pandas._libs.lib", "X"
+    "pandas.tslib", "pandas._libs.tslib", "X"
+    "pandas._join", "pandas._libs.join", ""
+    "pandas._period", "pandas._libs.period", ""
+    "pandas.msgpack", "pandas.io.msgpack", ""
+    "pandas.index", "pandas._libs.index", ""
+    "pandas.algos", "pandas._libs.algos", ""
+    "pandas.hashtable", "pandas._libs.hashtable", ""
+    "pandas.json", "pandas.io.json.libjson", "X"
+    "pandas.parser", "pandas.io.libparsers", "X"
+    "pandas.io.sas.saslib", "pandas.io.sas.libsas", ""
+    "pandas._testing", "pandas.util.libtesting", ""
+    "pandas._sparse", "pandas.sparse.libsparse", ""
+    "pandas._hash", "pandas.tools.libhash", ""
+    "pandas._window", "pandas.core.libwindow", ""
+
+
 .. _whatsnew_0200.api_breaking.groupby_describe:
 
 Groupby Describe Formatting

pandas/__init__.py

@@ -23,7 +23,9 @@
 from pandas.compat.numpy import *
 
 try:
-    from pandas import hashtable, tslib, lib
+    from pandas._libs import (hashtable as _hashtable,
+                             lib as _lib,
+                             tslib as _tslib)
 except ImportError as e:  # pragma: no cover
     # hack but overkill to use re
     module = str(e).lstrip('cannot import name ')
@@ -52,11 +54,17 @@
 from pandas.tools.util import to_numeric
 from pandas.core.reshape import melt
 from pandas.util.print_versions import show_versions
-
 from pandas.io.api import *
-
 from pandas.util._tester import test
 
+# extension module deprecations
+from pandas.util.depr_module import _DeprecatedModule
+
+json = _DeprecatedModule(deprmod='pandas.json', deprmodto='pandas.io.json.libjson')
+parser = _DeprecatedModule(deprmod='pandas.parser', deprmodto='pandas.io.libparsers')
+lib = _DeprecatedModule(deprmod='pandas.lib', deprmodto='pandas._libs.lib')
+tslib = _DeprecatedModule(deprmod='pandas.tslib', deprmodto='pandas._libs.tslib')
+
 # use the closest tagged version if possible
 from ._version import get_versions
 v = get_versions()

pandas/_libs/__init__.py

@@ -0,0 +1,8 @@
+# flake8: noqa
+
+from .tslib import iNaT, NaT, Timestamp, Timedelta, OutOfBoundsDatetime
+
+# TODO
+# period is directly dependent on tslib and imports python
+# modules, so exposing Period as an alias is currently not possible
+# from period import Period

pandas/algos.pyx pandas/_libs/algos.pyxpandas/algos.pyx renamed to pandas/_libs/algos.pyx

@@ -37,7 +37,7 @@ float64 = np.dtype(np.float64)
 cdef double NaN = <double> np.NaN
 cdef double nan = NaN
 
-cdef extern from "src/headers/math.h":
+cdef extern from "../src/headers/math.h":
     double sqrt(double x) nogil
     double fabs(double) nogil
 
@@ -46,7 +46,7 @@ from util cimport numeric, get_nat
 
 cimport lib
 from lib cimport is_null_datetimelike
-from pandas import lib
+from pandas._libs import lib
 
 cdef int64_t iNaT = get_nat()
 

pandas/src/algos_common_helper.pxi.in pandas/_libs/algos_common_helper.pxi.inpandas/src/algos_common_helper.pxi.in renamed to pandas/_libs/algos_common_helper.pxi.in

@@ -433,7 +433,7 @@ def arrmap_{{name}}(ndarray[{{c_type}}] index, object func):
 
     cdef ndarray[object] result = np.empty(length, dtype=np.object_)
 
-    from pandas.lib import maybe_convert_objects
+    from pandas._libs.lib import maybe_convert_objects
 
     for i in range(length):
         result[i] = func(index[i])