--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mde/file/mergetag/iface/IDataSection.d	Fri Aug 29 11:59:43 2008 +0100
@@ -0,0 +1,68 @@
+/* LICENSE BLOCK
+Part of mde: a Modular D game-oriented Engine
+Copyright © 2007-2008 Diggory Hardy
+
+This program 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 2 of the License, or (at your option) any later version.
+
+This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+/** This module contains the interface IDataSection used by DataSet.
+*
+* It has been given its own module to avoid cyclic dependancies and separate out the functionality
+* of mergetag.
+*
+* Also some base mergetag symbols have been moved here.
+*/
+module mde.file.mergetag.iface.IDataSection;
+
+/** Typedef for data & section indexes.
+*
+* Make it an alias, there doesn't appear to be any point having it as a typedef. */
+alias char[] ID;
+
+/**
+ * Interface for data storage classes, generally called DataSections, which contain all data-tags
+ * loaded from a single section of a file.
+ *
+ * A class implementing this may implement the addTag function to do whatever it likes with the
+ * data passed. DefaultData is one implementation which separates this data out into supported
+ * types and stores it appropriately (allowing merging with existing entries by keeping whichever
+ * tag was last loaded), while ignoring unsupported types. A different
+ * implementation could filter out the tags desired and use them directly, and ignore the rest.
+ *
+ * The mde.mergetag.parse.parseTo module provides a useful set of templated functions to
+ * convert the data accordingly. It is advised to keep the type definitions as defined in the file-
+ * format except for user-defined types, although this isn't necessary for library operation
+ * (addTag and writeAll are solely responsible for using and setting the type, ID and data fields).
+ *
+ * Another idea for a DataSection class:
+ * Use a void*[ID] variable to store all data (may also need a type var for each item).
+ * addTag should call a templated function which calls parse then casts to a void* and stores the data.
+ * Use a templated get(T)(ID) method which checks the type and casts to T.
+ */
+interface IDataSection
+{
+    /** Delegate passed to writeAll. */
+    typedef void delegate (char[],ID,char[]) ItemDelg;
+    
+    /** Handles parsing of data items for all recognised types.
+     *
+     * Should ignore unsupported types/unwanted tags.
+     *
+     * TextExceptions (thrown by parseTo/parseFrom) are caught and a warning logged; execution
+     * then continues (so the offending tag gets dropped). */
+    void addTag (char[],ID,char[]);
+    
+    /** Responsible for getting all data tags saved.
+    *
+    * writeAll should call the ItemDelg once for each tag to be saved with parameters in the same
+    * form as received by addTag (char[] type, ID id, char[] data). */
+    void writeAll (ItemDelg);
+}