Refactor exceptions and provide comment function.

libdevcore/Exceptions.cpp

@@ -0,0 +1,49 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <libdevcore/Exceptions.h>
+
+#include <boost/lexical_cast.hpp>
+
+using namespace std;
+using namespace dev;
+
+char const* Exception::what() const noexcept
+{
+	if (string const* cmt = comment())
+		return cmt->c_str();
+	else
+		return nullptr;
+}
+
+string Exception::lineInfo() const
+{
+	char const* const* file = boost::get_error_info<boost::throw_file>(*this);
+	int const* line = boost::get_error_info<boost::throw_line>(*this);
+	string ret;
+	if (file)
+		ret += *file;
+	ret += ':';
+	if (line)
+		ret += boost::lexical_cast<string>(*line);
+	return ret;
+}
+
+string const* Exception::comment() const noexcept
+{
+	return boost::get_error_info<errinfo_comment>(*this);
+}