[SPARK-7358][SQL] Move DataFrame mathfunctions into functions

After a discussion on the user mailing list, it was decided to put all UDF's under `o.a.s.sql.functions`

cc rxin

Author: Burak Yavuz <brkyvz@gmail.com>

Closes #5923 from brkyvz/move-math-funcs and squashes the following commits:

a8dc3f7 [Burak Yavuz] address comments
cf7a7bb [Burak Yavuz] [SPARK-7358] Move DataFrame mathfunctions into functions

3 files changed, 53 insertions, 102 deletions

diff --git a/python/pyspark/sql/functions.py b/python/pyspark/sql/functions.py
index 641220a264..692af868dd 100644
--- a/python/pyspark/sql/functions.py
+++ b/python/pyspark/sql/functions.py
@@ -51,6 +51,19 @@ def _create_function(name, doc=""):
     return _
 
 
+def _create_binary_mathfunction(name, doc=""):
+    """ Create a binary mathfunction by name"""
+    def _(col1, col2):
+        sc = SparkContext._active_spark_context
+        # users might write ints for simplicity. This would throw an error on the JVM side.
+        jc = getattr(sc._jvm.functions, name)(col1._jc if isinstance(col1, Column) else float(col1),
+                                              col2._jc if isinstance(col2, Column) else float(col2))
+        return Column(jc)
+    _.__name__ = name
+    _.__doc__ = doc
+    return _
+
+
 _functions = {
     'lit': 'Creates a :class:`Column` of literal value.',
     'col': 'Returns a :class:`Column` based on the given column name.',
@@ -63,6 +76,34 @@ _functions = {
     'sqrt': 'Computes the square root of the specified float value.',
     'abs': 'Computes the absolute value.',
 
+    # unary math functions
+    'acos': 'Computes the cosine inverse of the given value; the returned angle is in the range' +
+            '0.0 through pi.',
+    'asin': 'Computes the sine inverse of the given value; the returned angle is in the range' +
+            '-pi/2 through pi/2.',
+    'atan': 'Computes the tangent inverse of the given value.',
+    'cbrt': 'Computes the cube-root of the given value.',
+    'ceil': 'Computes the ceiling of the given value.',
+    'cos': 'Computes the cosine of the given value.',
+    'cosh': 'Computes the hyperbolic cosine of the given value.',
+    'exp': 'Computes the exponential of the given value.',
+    'expm1': 'Computes the exponential of the given value minus one.',
+    'floor': 'Computes the floor of the given value.',
+    'log': 'Computes the natural logarithm of the given value.',
+    'log10': 'Computes the logarithm of the given value in Base 10.',
+    'log1p': 'Computes the natural logarithm of the given value plus one.',
+    'rint': 'Returns the double value that is closest in value to the argument and' +
+            ' is equal to a mathematical integer.',
+    'signum': 'Computes the signum of the given value.',
+    'sin': 'Computes the sine of the given value.',
+    'sinh': 'Computes the hyperbolic sine of the given value.',
+    'tan': 'Computes the tangent of the given value.',
+    'tanh': 'Computes the hyperbolic tangent of the given value.',
+    'toDegrees': 'Converts an angle measured in radians to an approximately equivalent angle ' +
+             'measured in degrees.',
+    'toRadians': 'Converts an angle measured in degrees to an approximately equivalent angle ' +
+             'measured in radians.',
+
     'max': 'Aggregate function: returns the maximum value of the expression in a group.',
     'min': 'Aggregate function: returns the minimum value of the expression in a group.',
     'first': 'Aggregate function: returns the first value in a group.',
@@ -74,10 +115,21 @@ _functions = {
     'sumDistinct': 'Aggregate function: returns the sum of distinct values in the expression.',
 }
 
+# math functions that take two arguments as input
+_binary_mathfunctions = {
+    'atan2': 'Returns the angle theta from the conversion of rectangular coordinates (x, y) to' +
+             'polar coordinates (r, theta).',
+    'hypot': 'Computes `sqrt(a^2^ + b^2^)` without intermediate overflow or underflow.',
+    'pow': 'Returns the value of the first argument raised to the power of the second argument.'
+}
+
 for _name, _doc in _functions.items():
     globals()[_name] = _create_function(_name, _doc)
+for _name, _doc in _binary_mathfunctions.items():
+    globals()[_name] = _create_binary_mathfunction(_name, _doc)
 del _name, _doc
 __all__ += _functions.keys()
+__all__ += _binary_mathfunctions.keys()
 __all__.sort()
 
 
diff --git a/python/pyspark/sql/mathfunctions.py b/python/pyspark/sql/mathfunctions.py
deleted file mode 100644
index 7dbcab8694..0000000000
--- a/python/pyspark/sql/mathfunctions.py
+++ /dev/null
@@ -1,101 +0,0 @@
-#
-# Licensed to the Apache Software Foundation (ASF) under one or more
-# contributor license agreements.  See the NOTICE file distributed with
-# this work for additional information regarding copyright ownership.
-# The ASF licenses this file to You under the Apache License, Version 2.0
-# (the "License"); you may not use this file except in compliance with
-# the License.  You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-"""
-A collection of builtin math functions
-"""
-
-from pyspark import SparkContext
-from pyspark.sql.dataframe import Column
-
-__all__ = []
-
-
-def _create_unary_mathfunction(name, doc=""):
-    """ Create a unary mathfunction by name"""
-    def _(col):
-        sc = SparkContext._active_spark_context
-        jc = getattr(sc._jvm.mathfunctions, name)(col._jc if isinstance(col, Column) else col)
-        return Column(jc)
-    _.__name__ = name
-    _.__doc__ = doc
-    return _
-
-
-def _create_binary_mathfunction(name, doc=""):
-    """ Create a binary mathfunction by name"""
-    def _(col1, col2):
-        sc = SparkContext._active_spark_context
-        # users might write ints for simplicity. This would throw an error on the JVM side.
-        if type(col1) is int:
-            col1 = col1 * 1.0
-        if type(col2) is int:
-            col2 = col2 * 1.0
-        jc = getattr(sc._jvm.mathfunctions, name)(col1._jc if isinstance(col1, Column) else col1,
-                                                  col2._jc if isinstance(col2, Column) else col2)
-        return Column(jc)
-    _.__name__ = name
-    _.__doc__ = doc
-    return _
-
-
-# math functions are found under another object therefore, they need to be handled separately
-_mathfunctions = {
-    'acos': 'Computes the cosine inverse of the given value; the returned angle is in the range' +
-            '0.0 through pi.',
-    'asin': 'Computes the sine inverse of the given value; the returned angle is in the range' +
-            '-pi/2 through pi/2.',
-    'atan': 'Computes the tangent inverse of the given value.',
-    'cbrt': 'Computes the cube-root of the given value.',
-    'ceil': 'Computes the ceiling of the given value.',
-    'cos': 'Computes the cosine of the given value.',
-    'cosh': 'Computes the hyperbolic cosine of the given value.',
-    'exp': 'Computes the exponential of the given value.',
-    'expm1': 'Computes the exponential of the given value minus one.',
-    'floor': 'Computes the floor of the given value.',
-    'log': 'Computes the natural logarithm of the given value.',
-    'log10': 'Computes the logarithm of the given value in Base 10.',
-    'log1p': 'Computes the natural logarithm of the given value plus one.',
-    'rint': 'Returns the double value that is closest in value to the argument and' +
-            ' is equal to a mathematical integer.',
-    'signum': 'Computes the signum of the given value.',
-    'sin': 'Computes the sine of the given value.',
-    'sinh': 'Computes the hyperbolic sine of the given value.',
-    'tan': 'Computes the tangent of the given value.',
-    'tanh': 'Computes the hyperbolic tangent of the given value.',
-    'toDeg': 'Converts an angle measured in radians to an approximately equivalent angle ' +
-             'measured in degrees.',
-    'toRad': 'Converts an angle measured in degrees to an approximately equivalent angle ' +
-             'measured in radians.'
-}
-
-# math functions that take two arguments as input
-_binary_mathfunctions = {
-    'atan2': 'Returns the angle theta from the conversion of rectangular coordinates (x, y) to' +
-             'polar coordinates (r, theta).',
-    'hypot': 'Computes `sqrt(a^2^ + b^2^)` without intermediate overflow or underflow.',
-    'pow': 'Returns the value of the first argument raised to the power of the second argument.'
-}
-
-for _name, _doc in _mathfunctions.items():
-    globals()[_name] = _create_unary_mathfunction(_name, _doc)
-for _name, _doc in _binary_mathfunctions.items():
-    globals()[_name] = _create_binary_mathfunction(_name, _doc)
-del _name, _doc
-__all__ += _mathfunctions.keys()
-__all__ += _binary_mathfunctions.keys()
-__all__.sort()
diff --git a/python/pyspark/sql/tests.py b/python/pyspark/sql/tests.py
index 46c4c88e98..b232f3a965 100644
--- a/python/pyspark/sql/tests.py
+++ b/python/pyspark/sql/tests.py
@@ -416,7 +416,7 @@ class SQLTests(ReusedPySparkTestCase):
 
     def test_math_functions(self):
         df = self.sc.parallelize([Row(a=i, b=2 * i) for i in range(10)]).toDF()
-        from pyspark.sql import mathfunctions as functions
+        from pyspark.sql import functions
         import math
 
         def get_values(l):