BLD: Use tempita for cython templating

closes #13399

Author: sinhrks <[email protected]>

Closes #13716 from sinhrks/tempita and squashes the following commits:

09f63b6 [sinhrks] BLD: Use tempita for cython templating

Author: sinhrks

ci/lint.sh

@@ -23,14 +23,26 @@ if [ "$LINT" ]; then
     for path in 'window.pyx'
     do
         echo "linting -> pandas/$path"
-        flake8 pandas/$path --filename '*.pyx' --select=E501,E302,E203,E226,E111,E114,E221,E303,E128,E231,E126,E128
+        flake8 pandas/$path --filename '*.pyx' --select=E501,E302,E203,E226,E111,E114,E221,E303,E128,E231,E126
         if [ $? -ne "0" ]; then
             RET=1
         fi
 
     done
     echo "Linting *.pyx DONE"
 
+    echo "Linting *.pxi.in"
+    for path in 'src'
+    do
+        echo "linting -> pandas/$path"
+        flake8 pandas/$path --filename '*.pxi.in' --select=E501,E302,E203,E111,E114,E221,E303,E231,E126
+        if [ $? -ne "0" ]; then
+            RET=1
+        fi
+
+    done
+    echo "Linting *.pxi.in DONE"
+
     echo "Check for invalid testing"
     grep -r -E --include '*.py' --exclude nosetester.py --exclude testing.py '(numpy|np)\.testing' pandas
     if [ $? = "0" ]; then

pandas/algos.pyx

@@ -13,6 +13,7 @@ cdef float64_t FP_ERR = 1e-13
 cimport util
 
 from libc.stdlib cimport malloc, free
+from libc.string cimport memmove
 
 from numpy cimport NPY_INT8 as NPY_int8
 from numpy cimport NPY_INT16 as NPY_int16
@@ -41,10 +42,14 @@ cdef extern from "src/headers/math.h":
     double fabs(double) nogil
 
 # this is our util.pxd
-from util cimport numeric
+from util cimport numeric, get_nat
 
+cimport lib
+from lib cimport is_null_datetimelike
 from pandas import lib
 
+cdef int64_t iNaT = get_nat()
+
 cdef:
     int TIEBREAK_AVERAGE = 0
     int TIEBREAK_MIN = 1
@@ -1334,5 +1339,11 @@ cdef inline float64_t _median_linear(float64_t* a, int n):
 
     return result
 
+
 include "join.pyx"
-include "generated.pyx"
+
+# generated from template
+include "algos_common_helper.pxi"
+include "algos_groupby_helper.pxi"
+include "algos_join_helper.pxi"
+include "algos_take_helper.pxi"