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Today's Topics:
1. Critique My First Project - CampBX API Client (Pavan Rikhi)
----------------------------------------------------------------------
Message: 1
Date: Sat, 19 Jul 2014 03:57:25 -0400
From: Pavan Rikhi <[email protected]>
To: [email protected]
Subject: [Haskell-beginners] Critique My First Project - CampBX API
Client
Message-ID: <[email protected]>
Content-Type: text/plain; charset="us-ascii"
Hiya, so I've spent the last 2 months or so learning Haskell. I've
finished the UPenn course, LYAH and a little bit of RWH.
I wanted to get a project going so I tried making an API client for the
CampBX Bitcoin Market[1]. I started out by following along with the
FPComplete Mailchimp API Tutorial[2].
I'm asking you beautiful people for any feedback on it so I can be sure
that I'm on the right track here, stuff like code style/idioms, project
layout, public interface, implementation, docs, ideas for new features,
anything you want to tell me, etc.:
https://github.com/prikhi/campbx-haskell
Typical usage would be something like this[3]:
main :: IO ()
main = do
cfg <- defaultCampBXConfig
_ <- runCampBX cfg $ do
totalAskVolume <- calculateAskVolume <$> getDepth
liftIO . putStrLn $ "Total Ask Volume: " ++ show totalAskVolume
return ()
calculateAskVolume :: Depth -> BTCAmount
calculateAskVolume depthList = sum . map askPrice . asks $ depthList
where askPrice (Ask (_, q)) = q
There are still some things I want to work on:
* Define Asks and Bids[4] using Record Syntax. The JSON[5] for a Bid/Ask
comes back as a 2 item Array but the generically derived instance[6]
expects an object. I haven't completely wrapped my head around Aeson's
Array parsing...
* Write tests. I'm imagining they would be more "given this JSON, make
sure the data structure is created correctly" instead of
property-based testing.
* Use something other than Doubles to represent Amounts + Prices. Is
there a standard library for accurate math with decimals(I need up to
8 decimal places)? I suppose I could always just use Integers to
represent Satoshis(the smallest subunit of bitcoins).
Also I tried adding "default-extensions: OverloadedStrings" to the
.cabal file and removing the pragmas from the source files, but the
package wouldn't build :(
[1] https://campbx.com/api.php
[2]
https://www.fpcomplete.com/school/to-infinity-and-beyond/competition-winners/interfacing-with-restful-json-apis
[3] https://github.com/prikhi/campbx-haskell/blob/master/bin/CampBXMain.hs
[4]
https://github.com/prikhi/campbx-haskell/blob/master/src/Web/CampBX/Types.hs#L71
[5] http://sleepanarchy.com/p/K1wuSm
[6]
https://github.com/prikhi/campbx-haskell/blob/master/src/Web/CampBX/Types.hs#L188
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