I noticed that in Takusen there're just two instances to implement to make any Haskell type db-serializable: DBBind / SqliteBind for serialization and DBType for deserialization.
I wanted to implement blob serialization for PackedStrings, but I noticed that both DBBind and DBType classes are not public. Defining custom serialization (not just Show / Read string serialization) is very useful in applicative code, and not just in Takusen backend code.
There's any way to do it without modifying Takusen Sqlite backend?
Salvatore Insalaco
Sorry, not at present. It shouldn't be hard to modify the code though, and PackedString support is something we should really be thinking about anyway (as well as Blobs, which I think should have a different type). Although DBType is a class in InternalEnumerator (so you'd think it might be easy to extend with new types), in practice we do not expose the internal Query and ColumnBuffer objects that you also need to create new instances of the class, so you're stuck with what we provide. This is intentional; you usually need to access the low-level buffers and other resources to write an instance on DBType, and we don't want to expose these details to users. By hiding this stuff, we can ensure that resources are properly cleaned up when queries and commands complete. So, please take this as an invitation to modity the Sqlite implementation to handle PackedStrings (and Blobs, if you want to). BTW, do you really need to marshall PackedStrings to blobs? The Sqlite library uses CStrings, and I assume that CString to PackedString marshaling is fairly efficient, so that would seem to be a better choice. (I have no experience of PackedStrings, so there might be good reasons to prefer blobs, and I'd like to know what they are.) Alistair ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************