Hello,
I recently added default generic implementations of toJSON and
parseJSON to the aeson package. Now I'm optimizing them. Here are some
benchmark results that compare:
* th: toJSON and fromJSON generated by template-haskell. Can be
compared to hand-written code. Should be the fastest of
Hi Bas,
First of all, thanks for these numbers. I have previously compared the
performance of GP libs [1] and your results confirm what I would expect,
except for that last one, BigSum/fromJSON/generic.
It's good that you're using INLINE pragmas on the generic function already.
What I would also
2011/11/3 José Pedro Magalhães j...@cs.uu.nl:
- Compile with -O2 and -fno-spec-constr-count (this last one is particularly
important)
I already compiled with -O2. Adding -fno-spec-constr-count does not
change the results.
- Add {-# INLINE [1] #-} pragmas to the to/from methods of your Generic
For those who find this interesting. Here's the code of the BigSum benchmark
with a manual Generic instance with inlined 'from' and 'to':
https://gist.github.com/1336426
José, I was thinking about the following idea. Say GHC generates the
following instance for BigSum:
instance Generic BigSum
* syb: toJSON and fromJSON from the Data.Aeson.Generic module. Uses
the Data type class.
..
As can be seen, in most cases the GHC Generics implementation is much
faster than SYB and just as fast as TH. I'm impressed by how well GHC
optimizes the code!
Not that it matters much if you're going
2011/11/3 Claus Reinke claus.rei...@talk21.com:
Not that it matters much if you're going with other tools, but your SYB code
has a long linear chain of type rep comparisons, at every
level of the recursive traversals. That is partially inherent in the SYB
design (reducing everything to cast),
On 03/11/11 11:16, Bas van Dijk wrote:
...
instance (Constructor c, GFromJSON a, ConsFromJSON a) = GFromSum (C1 c a) where
gParseSum (key, value)
| key == pack (conName (undefined :: t c a p)) =
gParseJSON value
| otherwise = notFound $ unpack key
{-#
On 3 November 2011 17:38, Twan van Laarhoven twa...@gmail.com wrote:
Perhaps relying on Attoparsec backtracking for picking out the right
alternative from the sum is the problem. You could try it with Maybe:
Good idea. I implemented and committed it and the
BigSum/fromJSON/generic benchmark
