There are a lot of advantages to programming in a typed functional language like haskell. + Certain bugs, like misuse of global variables, are virtually impossible unless you bend over backwards + to do things wrong. Code tends to be incredibly short, and modular. The haskell community is very + friendly, and with coders in every time zone the #haskell irc channel seems well populated + seemingly 24 hours a day. + +
But we're here to talk about HAppS, not haskell. + +
What got me interested in HAppS was a strongly held feeling that as +modern software systems tend toward ever increasing complexity, +database usage is an unnecessary source of complication that +should be factored out where possible. + +
Ruby's rails and python's django have become popular largely because of their object relational mapping systems, +which hide the complexity of database engines by converting application data manipulation logic into sql. +When I first used an ORM, it felt like a huge improvement over writing sql statements every time I wanted to manipulate +an application's state. But pretty soon ORMs started seeming hackish to me too. At some point, +the metaphors I wanted to use just broke down. + + +$!Or to put it another way, that sql +is an ugly hack. !$ +
HAppS is haskell's answer to rails and django (and perl's catalyst, + and php). + + With HAppS, there is no wrangling data + structures into and out of the database, because there is no database. You use whatever data + structures are natural to your application, and serialize them + transparently using + powerful + machinery that's running behind the + scenes. And if there are existing databases that you need to connect to, you can do that too + -- you're not locked in to using macid for everything. + +
MACID, +the HAppS storage mechanism, is no vanilla serialization layer that will +start acting in weird ways when an application has many concurrent users doing possibly conflicting things. +By leveraging haskell's type system +(see composable memory transactions paper), +you get the same ACID guarantees that +normally only come with a database.
+ + +There are some limitations to using macid + as a datastore that you should familiarize yourself with + if you are looking into using HAppS for heavy-usage transactional applications. + But long term, HAppS with macid looks promising enough that I've started + using it as a platform for building commercial web 2.0 type apps. (My first + commercial happs app will be public soon, so stay tuned on + techcrunch. :) ) + +
In short, HAppS is awesome, and webmonkeys everywhere should use it. Except... + +
Well, nothing is perfect. + + + +