Nice.
Do you think there is any reason we would not be able to / want to use
it with happstack ? I would love happstack-data to 'go away' and just
use some library from hackage which does the same thing.
- jeremy
On Dec 17, 2010, at 3:57 AM, Erik Hesselink wrote:
I've recently been playing with code for versioning data types. It's
based on happstacks implementation, but uses type families to make it
more modular. I've got some proof of concept code on github [1]. We're
also writing a small library based on this at typLAB, which we'll
probably release as well.
Erik
[1] https://gist.github.com/704109
On Thu, Dec 16, 2010 at 19:26, Dmitry V'yal <akam...@gmail.com> wrote:
Greetings,
while developing my neural net simulator I stumbled upon a problem.
I have a data type NeuralNet and use Show and Read instances for
saving and
loading configurations. As time passed, I changed the data type, so
the
program can no longer load files saved in previous versions.
I want fix it. My current idea looks as follows. I'm going to
create a bunch
of types NN1, NN2, NN3..NNn for different versions and write
converters c12
:: N1 -> N2, c23 :: N2 -> N3 and so on.
But how to organize the whole process of parsing String into NNn so
it's
easy to change formats?
Something based on using a list of parsers
[read, c43 . read, c43 . c23 . read, c43, c23 . c12 . read, c43 .
c32 . c21
. read]
looks rather verbose and grows quadratically with N.
I'm sure there must be a more elegant way. Any ideas?
Dmitry
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
