Index: libcfa/src/exception.hfa
===================================================================
--- libcfa/src/exception.hfa	(revision e68d09236d814efe89f3e680ef44217ed691df67)
+++ libcfa/src/exception.hfa	(revision e68d09236d814efe89f3e680ef44217ed691df67)
@@ -0,0 +1,106 @@
+//
+// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
+//
+// The contents of this file are covered under the licence agreement in the
+// file "LICENCE" distributed with Cforall.
+//
+// exception.hfa -- User facing tools for working with exceptions.
+//
+// Author           : Andrew Beach
+// Created On       : Thu Apr  7 10:25:00 2020
+// Last Modified By : Andrew Beach
+// Last Modified On : Thu Apr  7 10:25:00 2020
+// Update Count     : 0
+//
+
+// Everything below this line should be considered a patch while the exception
+// objects themselves are designed and  created and should be removed in time.
+// -----------------------------------------------------------------------------------------------
+
+// All internals helper macros begin with an underscore.
+#define _CLOSE(...) __VA_ARGS__ }
+#define _GLUE2(left, right) left##right
+#define _GLUE3(left, middle, right) left##middle##right
+#define _EXC_DISPATCH(to, ...) to(__VA_ARGS__,__cfaehm_base_exception_t,)
+
+// FWD_TRIVIAL_EXCEPTION(exception_name);
+// Declare a trivial exception, one that adds no fields or features.
+// This will make the exception visible and may go in a .hfa or .cfa file.
+#define FWD_TRIVIAL_EXCEPTION(...) _EXC_DISPATCH(_FWD_TRIVIAL_EXCEPTION, __VA_ARGS__)
+// INST_TRIVIAL_EXCEPTION(exception_name);
+// Create the trival exception. This must be used exactly once and should be used in a .cfa file,
+// as it creates the unique instance of the virtual table.
+#define INST_TRIVIAL_EXCEPTION(...) _EXC_DISPATCH(_INST_TRIVIAL_EXCEPTION, __VA_ARGS__)
+// TRIVIAL_EXCEPTION(exception_name[, parent_name]);
+// Does both of the above, a short hand if the exception is only used in one .cfa file.
+// For legacy reasons this is the only one that official supports having a parent other than the
+// base exception. This feature may be removed or changed.
+#define TRIVIAL_EXCEPTION(...) \
+	_EXC_DISPATCH(_FWD_TRIVIAL_EXCEPTION, __VA_ARGS__); \
+	_EXC_DISPATCH(_INST_TRIVIAL_EXCEPTION, __VA_ARGS__)
+#define _FWD_TRIVIAL_EXCEPTION(exception_name, parent_name, ...) \
+	_VTABLE_DECLARATION(exception_name, parent_name)(); \
+	struct exception_name { \
+		VTABLE_FIELD(exception_name); \
+	}; \
+	void ?{}(exception_name & this); \
+	const char * _GLUE2(exception_name,_msg)(exception_name * this)
+#define _INST_TRIVIAL_EXCEPTION(exception_name, parent_name, ...) \
+	void ?{}(exception_name & this) { \
+		VTABLE_INIT(this, exception_name); \
+	} \
+	const char * _GLUE2(exception_name,_msg)(exception_name * this) { \
+		return #exception_name; \
+	} \
+	_VTABLE_INSTANCE(exception_name, parent_name,)(_GLUE2(exception_name,_msg))
+
+// DATA_EXCEPTION(exception_name)(fields...);
+// Forward declare an exception that adds fields but no features. The added fields go in the
+// second argument list. The virtual table instance must be provided later (see VTABLE_INSTANCE).
+#define DATA_EXCEPTION(...) _EXC_DISPATCH(_DATA_EXCEPTION, __VA_ARGS__)
+#define _DATA_EXCEPTION(exception_name, parent_name, ...) \
+	_VTABLE_DECLARATION(exception_name, parent_name)(); \
+	struct exception_name { VTABLE_FIELD(exception_name); _CLOSE
+
+// VTABLE_DECLARATION(exception_name)([new_features...]);
+// Declare a virtual table type for an exception with exception_name. You may also add features
+// (fields on the virtual table) by including them in the second list.
+#define VTABLE_DECLARATION(...) _EXC_DISPATCH(_VTABLE_DECLARATION, __VA_ARGS__)
+#define _VTABLE_DECLARATION(exception_name, parent_name, ...) \
+	struct exception_name; \
+	VTABLE_TYPE(exception_name); \
+	extern VTABLE_TYPE(exception_name) VTABLE_NAME(exception_name); \
+	VTABLE_TYPE(exception_name) { \
+		VTABLE_TYPE(parent_name) const * parent; \
+		size_t size; \
+		void (*copy)(exception_name * this, exception_name * other); \
+		void (*free)(exception_name & this); \
+		const char * (*msg)(exception_name * this); \
+		_CLOSE
+
+// VTABLE_INSTANCE(exception_name)(msg [, others...]);
+// Create the instance of the virtual table. There must be exactly one instance of a virtual table
+// for each exception type. This fills in most of the fields of the virtual table (uses ?=? and
+// ^?{}) but you must provide the message function and any other fields added in the declaration.
+#define VTABLE_INSTANCE(...) _EXC_DISPATCH(_VTABLE_INSTANCE, __VA_ARGS__)
+#define _VTABLE_INSTANCE(exception_name, parent_name, ...) \
+	void _GLUE2(exception_name,_copy)(exception_name * this, exception_name * other) { \
+		*this = *other; \
+	} \
+	VTABLE_TYPE(exception_name) VTABLE_NAME(exception_name) @= { \
+		&VTABLE_NAME(parent_name), sizeof(exception_name), \
+		_GLUE2(exception_name,_copy), ^?{}, \
+		_CLOSE
+
+// VTABLE_TYPE(exception_name) | VTABLE_NAME(exception_name)
+// Get the name of the vtable type or the name of the vtable instance for an exception type.
+#define VTABLE_TYPE(exception_name) struct _GLUE2(exception_name,_vtable)
+#define VTABLE_NAME(exception_name) _GLUE3(_,exception_name,_vtable_instance)
+
+// VTABLE_FIELD(exception_name);
+// The declaration of the virtual table field. Should be the first declaration in a virtual type.
+#define VTABLE_FIELD(exception_name) VTABLE_TYPE(exception_name) const * virtual_table
+
+// VTABLE_INIT(object_reference, exception_name);
+// Sets a virtual table field on an object to the virtual table instance for the type.
+#define VTABLE_INIT(this, exception_name) (this).virtual_table = &VTABLE_NAME(exception_name)