This is a fascinating project. Haxl is the brainchild of former Glasgow Haskell Compiler lead* Simon Marlow.
The tl;dr of Haxl: what if you could describe accessing a data store (a la SQL) and have the compiler and library work together to "figure out" the most efficient way to perform queries, including performing multiple queries in parallel? That's what Haxl does, it allows you to specify the "shape" of your query, the type checker verifies its correctness, and the library executes it in parallel for you, without the developer having to know about synchronizing access or anything.
It's a great read indeed. If anyone is interested in more concrete applications of Haskell then a read through this should be enough to convince anyone that we can do some really amazing parallel programming on top of Haskell's RTS.
Is it a cultural reference? Found it in bestcomments, so looks like many people do get it, but I don't. Genuinely interested having English as a second language.
I haven't used databases much, but don't most SQL implementations already "figure out" the most efficient way to perform queries? Can't most implementations already perform queries in parallel?
Yes, but this is designed for non-SQL datastores, and arbitrary application code connecting portions of "data acquisition" and "data operation". Imagine if instead of an ORM, you had a single system that weaved together your application code and the database queries, and ensured that where they could execute in parallel, they did.
Yes, but this is for non-SQL systems, and it does quite a bit more. It's more like an ORM in this respect, because it weaves together the query planning and processing part which handles retrieving data, and the execution of operating on that data.
The tl;dr of Haxl: what if you could describe accessing a data store (a la SQL) and have the compiler and library work together to "figure out" the most efficient way to perform queries, including performing multiple queries in parallel? That's what Haxl does, it allows you to specify the "shape" of your query, the type checker verifies its correctness, and the library executes it in parallel for you, without the developer having to know about synchronizing access or anything.
Here's a link to their paper (PDF): http://www.haskell.org/wikiupload/c/cf/The_Haxl_Project_at_F...
* - I am not sure if he's still committing, or if he's only doing application development. His accomplishments in Haskell land though, are many.
Edited: I removed my comment about GitHub issues, seems it's a known problem. :)