Change structure of EWF, to follow better categorization

library/utility/general/error/src/error.e

@@ -0,0 +1,92 @@
+note
+	description : "Objects that represent an error"
+	legal: "See notice at end of class."
+	status: "See notice at end of class."
+	date: "$Date$"
+	revision: "$Revision$"
+
+deferred class
+	ERROR
+
+inherit
+	ANY
+
+	DEBUG_OUTPUT
+
+feature -- Access
+
+	code: INTEGER
+		deferred
+		ensure
+			result_not_zero: Result /= 0
+		end
+
+	name: READABLE_STRING_8
+		deferred
+		ensure
+			result_attached: Result /= Void
+		end
+
+	message: detachable READABLE_STRING_32
+			-- Potential error message
+		deferred
+		end
+
+	parent: detachable ERROR
+			-- Eventual error prior to Current
+
+feature -- String representation
+
+	string_representation: STRING_32
+			-- String representation for Current
+		do
+			create Result.make_from_string (name.as_string_32)
+			Result.append_character (' ')
+			Result.append_character ('(')
+			Result.append_integer (code)
+			Result.append_character (')')
+			if attached message as m then
+				Result.append_character (':')
+				Result.append_character (' ')
+				Result.append_string (m)
+			end
+		end
+
+feature -- Status report
+
+	debug_output: STRING
+		do
+			Result := string_representation.as_string_8
+		end
+
+feature -- Change
+
+	set_parent (a_parent: like parent)
+			-- Set `parent' to `a_parent'
+		do
+			parent := a_parent
+		end
+
+feature -- Visitor
+
+	process (a_visitor: ERROR_VISITOR)
+			-- Process Current using `a_visitor'.
+		require
+			a_visitor_not_void: a_visitor /= Void
+		deferred
+		end
+
+invariant
+	name_attached: name /= Void
+
+note
+	copyright: "2011-2012, Eiffel Software and others"
+	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
+	source: "[
+			Eiffel Software
+			5949 Hollister Ave., Goleta, CA 93117 USA
+			Telephone 805-685-1006, Fax 805-685-6869
+			Website http://www.eiffel.com
+			Customer support http://support.eiffel.com
+		]"
+end