export misc::generic_error to python (closes #199)

doc/new/_posts/2000-11-28-indices.md

@@ -77,8 +77,8 @@ __tabsMid
 ~~~ python
 try:
     c(j) << A(i,j) * b(j) # runtime error!
-except xerus.misc.generic_error as err:
-    print("something went wrong:", err.what())
+except xerus.generic_error as err:
+    print("something went wrong:", err)
 ~~~
 __tabsEnd
 

src/unitTests/indices.cxx

+// Xerus - A General Purpose Tensor Library
+// Copyright (C) 2014-2016 Benjamin Huber and Sebastian Wolf. 
+// 
+// Xerus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+// 
+// Xerus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Affero General Public License for more details.
+// 
+// You should have received a copy of the GNU Affero General Public License
+// along with Xerus. If not, see <http://www.gnu.org/licenses/>.
+//
+// For further information on Xerus visit https://libXerus.org 
+// or contact us at contact@libXerus.org.
+
+
+#include<xerus.h>
+
+#include "../../include/xerus/test/test.h"
+#include "../../include/xerus/misc/internal.h"
+using namespace xerus;
+
+static misc::UnitTest failtest("Index", "invalid_spans", [](){
+#ifdef XERUS_DISABLE_RUNTIME_CHECKS
+	LOG(warning, "failtests skipped due to XERUS_DISABLE_RUNTIME_CHECKS");
+#else
+	Index i,j;
+	Tensor c;
+	Tensor A = Tensor::random({10,10});
+	Tensor b = Tensor::random({10});
+	
+	try {
+		A(i,j^2) = A(j^2,i);
+		MTEST(false, "A(j^2,i) did not throw!");
+	} catch (misc::generic_error &_e) {
+		TEST(true);
+	} catch (...) {
+		MTEST(false, "threw a wrong exception class!");
+	}
+	
+	try {
+		A(i,j) = A(j,i&0);
+		MTEST(false, "A(j^2,i) did not throw!");
+	} catch (misc::generic_error &_e) {
+		TEST(true);
+	} catch (...) {
+		MTEST(false, "threw a wrong exception class!");
+	}
+	
+	try {
+		A(i,j) = A(j,i/1);
+		MTEST(false, "A(j^2,i) did not throw!");
+	} catch (misc::generic_error &_e) {
+		TEST(true);
+	} catch (...) {
+		MTEST(false, "threw a wrong exception class!");
+	}
+	
+	try {
+		A(i,j) = A(j,i/3);
+		MTEST(false, "A(j^2,i) did not throw!");
+	} catch (misc::generic_error &_e) {
+		TEST(true);
+	} catch (...) {
+		MTEST(false, "threw a wrong exception class!");
+	}
+	
+	try {
+		c(j) = A(i,j) * b(j);
+		MTEST(false, "c(j)=... did not throw!");
+	} catch (misc::generic_error &_e) {
+		TEST(true);
+	} catch (...) {
+		MTEST(false, "threw a wrong exception class!");
+	}
+#endif
+});

src/unitTests/tensor.cxx

@@ -288,3 +288,4 @@ static misc::UnitTest tensor_sparse_dense("Tensor", "Sparse_Dense_Conversions",
 });
 
 
+

src/xerus/python/python.cpp

@@ -1206,9 +1206,15 @@ BOOST_PYTHON_MODULE(xerus) {
 	// identity returns the cpp name to a python object
 // 	def("identity", identity_);
 	
-	// the following is probably not necessary because generic_error inherits from std::exception
-// 	register_exception_translator<misc::generic_error>([](const misc::generic_error &_e){
-// 		LOG(pydebug, "custom exception handler called with " << _e.what());
-// 		PyErr_SetString(PyExc_UserWarning, _e.what());
-// 	});
+	def("xethrow", +[](){XERUS_THROW(misc::generic_error() << misc::get_call_stack());});
+	
+	// translate all exceptions thrown inside xerus to own python exception class
+	static char fully_qualified_gen_error_name[] = "xerus.generic_error";
+	static PyObject* py_gen_error = PyErr_NewException(fully_qualified_gen_error_name, PyExc_Exception, 0);
+    py::scope().attr("generic_error") = py::handle<>(py::borrowed(py_gen_error));
+
+	register_exception_translator<misc::generic_error>([](const misc::generic_error &_e){
+		LOG(pydebug, "custom exception handler called with " << _e.what());
+		PyErr_SetString(py_gen_error, _e.what());
+	});
 }