add a simple swig example (from the turorial)

Makefile

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+.PHONY: default
+default: all test
+
+.PHONY: all
+all: _test_swig.so
+
+.PHONY: test
+test:
+	python2.7 test_swig_test.py
+
+_test_swig.so: test_swig.o
+	ld -shared test_swig.o test_swig_wrap.o -o _test_swig.so
+
+test_swig.o: test_swig_wrap.c
+	gcc -fpic -c test_swig.c test_swig_wrap.c -I/usr/include/python2.7
+
+test_swig_wrap.c: test_swig.i
+	swig -python $<
+
+.PHONY: clean
+clean:
+	rm -f *.o *.so test_swig_wrap.c *.pyc test_swig.py

test_swig.c

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+/* Example from the SWIG tutorial */
+
+#include <time.h>
+
+double My_variable = 3.0;
+
+int fact(int n) {
+  if (n <= 1) return 1;
+  else return n*fact(n-1);
+}
+
+int my_mod(int x, int y) {
+  return (x%y);
+}
+
+char *get_time() {
+  time_t ltime;
+  time(&ltime);
+  return ctime(&ltime);
+}

test_swig.i

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+ /* Example from the SWIG tutorial */
+ %module test_swig
+ %{
+ /* Put header files here or function declarations like below */
+ extern double My_variable;
+ extern int fact(int n);
+ extern int my_mod(int x, int y);
+ extern char *get_time();
+ %}
+
+ extern double My_variable;
+ extern int fact(int n);
+ extern int my_mod(int x, int y);
+ extern char *get_time();

test_swig_test.py

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+from __future__ import division, print_function
+import test_swig
+
+# FIXME
+#print(test_swig.My_variable)
+#assert(test_swig.My_variable == 3.0)
+
+print(test_swig.fact(5))
+assert(test_swig.fact(5) == 120)
+
+print(test_swig.my_mod(23, 5))
+assert(test_swig.my_mod(23, 5) == 3)
+
+print(test_swig.get_time(), end="")
+assert(len(test_swig.get_time()) > 20)