From 7c5ced26f18d29bad4aa7fa14c6c8feba2e269ab Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 6 Aug 2008 16:29:57 +0000
Subject: [PATCH] Add a "where" property to Exception class

---
 source/core/except.cpp | 25 +++++++++++++++++--------
 source/core/except.h   | 14 +++++++++++---
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/source/core/except.cpp b/source/core/except.cpp
index ddd2cb5..0ae2e59 100644
--- a/source/core/except.cpp
+++ b/source/core/except.cpp
@@ -1,7 +1,7 @@
 /* $Id$
 
 This file is part of libmspcore
-Copyright © 2006-2007 Mikko Rasa, Mikkosoft Productions
+Copyright © 2006-2008  Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
 
@@ -16,24 +16,27 @@ using namespace std;
 
 namespace Msp {
 
-Exception::Exception(const string &w_):
-	w(w_)
+Exception::Exception(const string &w):
+	wot(w)
 {
 #ifdef WITH_EXCEPTION_BACKTRACE
 	bt=Debug::Backtrace::create();
 #endif
 }
 
+Exception &Exception::at(const std::string &w) throw()
+{
+	wer=w;
+	wot=wer+": "+wot;
+	return *this;
+}
+
+
 SystemError::SystemError(const string &w_, int e):
 	Exception(build_what(w_, e)),
 	err(e)
 { }
 
-KeyError::KeyError(const string &w_, const string &k):
-	Exception(w_+" ("+k+")"),
-	key(k)
-{ }
-
 string SystemError::build_what(const string &w, int e)
 {
 	ostringstream buf;
@@ -50,4 +53,10 @@ string SystemError::build_what(const string &w, int e)
 	return buf.str();
 }
 
+
+KeyError::KeyError(const string &w_, const string &k):
+	Exception(w_+" ("+k+")"),
+	key(k)
+{ }
+
 } // namespace Msp
diff --git a/source/core/except.h b/source/core/except.h
index 5dfbe8d..fc6fcc6 100644
--- a/source/core/except.h
+++ b/source/core/except.h
@@ -1,9 +1,10 @@
 /* $Id$
 
 This file is part of libmspcore
-Copyright © 2006-2007 Mikko Rasa, Mikkosoft Productions
+Copyright © 2006-2008  Mikko Rasa, Mikkosoft Productions
 Distributed under the LGPL
 */
+
 #ifndef MSP_CORE_ERROR_H_
 #define MSP_CORE_ERROR_H_
 
@@ -22,10 +23,13 @@ public:
 	Exception(const std::string &);
 	~Exception() throw() { }
 
-	const char *what() const throw() { return w.c_str(); }
+	const char *what() const throw() { return wot.c_str(); }
+	Exception &at(const std::string &) throw();
+	const char *where() const throw() { return wer.c_str(); }
 	const Debug::Backtrace &get_backtrace() const throw() { return bt; }
 private:
-	std::string w;
+	std::string wot;
+	std::string wer;
 	Debug::Backtrace bt;
 
 };
@@ -88,6 +92,10 @@ private:
 	static std::string build_what(const std::string &, int);
 };
 
+template<typename E>
+void throw_at(E e, const std::string &a)
+{ e.at(a); throw e; }
+
 } // namespace Msp
 
 #endif
-- 
2.43.0