domdere / cassava-conduit

Conduit interface for cassava [Haskell]

Dom De Re

About

👋 Hi, I’m @domdere, a Game Developer and avid Functional Programmer based in Sydney, Australia.

I run a small game dev studio in Sydney called 👉Irreverent Pixel Feats 👈.

We're working on our first commercial title, but also try and produce small free games during Game Jams and whatnot, as well as providing work-for-hire for other developers working on bigger projects.

Games I've Been Involved In

• Moving Out 2 📦 ✌️ (Senior Unity Dev)

Socials and Sites

• Twitter
• Irreverent Pixel Feats

cassava-conduit's Issues

Uploading to Stackage?

Hi! Thanks for the great package, it's been very useful to me! :D Just wondering if there any plans to put cassava-conduit onto the stackage package database?

(If you wanted to, it's as simple as editing this file)

Relax upper bounds on bytestring, possibly text

The package is compiling fine in our project with lts-20.2 and allow-newer: true, so I suspect it's just a bounds revision that's needed. Could you relax those so we can remove the allow-newer: true?

For reference, https://github.com/commercialhaskell/stackage/blob/master/build-constraints.yaml#L6108-L6109

Adding a header variant of toCsv

Thanks for this package, its super useful.

I want to add a new method to allow streaming out to a CSV file using a header, but I am strugglig to build the project with Mafia.

I think the code should be pretty simple:

toNamedCsv :: (Monad m, ToNamedRecord a) => Header -> EncodeOptions -> ConduitT a BS.ByteString m ()
toNamedCsv header opts = {-# SCC toCsv_p #-} map $ BSL.toStrict . encodeWithName header opts . pure

Anyway, let me know if something like this would be accepted and I'll persevere setting up mafia 😅

Benchmark build failure (Critereon.Types does not export Pure)

Preprocessing library cassava-conduit-0.3.2...
Preprocessing benchmark 'benchmarks' for cassava-conduit-0.3.2...
[1 of 1] Compiling Main             ( benchmarks/Main.hs, dist/build/benchmarks/benchmarks-tmp/Main.o )

benchmarks/Main.hs:10:26: error:
    Module ‘Criterion.Types’ does not export ‘Pure’

Here's one way to reproduce:

$ stack unpack cassava-conduit-0.3.2 && cd cassava-conduit-0.3.2
$ stack init --resolver nightly-2016-07-19
$ stack bench

toNamedCsv

Great library, thanks for developing and maintaining it!

One weak point, though, is writing .csv files back to the file system. Probably you didn't need this functionality for your use-case. To my understanding at the moment cassava-conduit only includes a very basic toCsv function:

toCsv :: (Monad m, ToRecord a) => EncodeOptions -> ConduitT a BS.ByteString m ()
toCsv opts = {-# SCC toCsv_p #-} map $ BSL.toStrict . encodeWith opts . pure

with a comment indicating that this was more of an afterthought: "Streams from csv to text, does not create headers...".

I would like to know if it would be possible to add a function toNamedCsv, which makes use of the ToNamedRecord class in cassava to automatically write with column names. This is important functionality for my application. Are there special challenges involved with this or was it just not a priority for you so far?

I saw that there is an alternative with the csv-conduit library, which seems to have this functionality. But of course I would prefer to stay with cassava, which I understand already, over a completely different library.

Add headers variant redux

I have a source that doesn't support being treated like a filehandle, nor does it support being updated after "writing the file" so to speak.

I noticed discussion in #28 about using multiple producers and slightly modified some code from there:

toNamedDefaultOrderCsv :: (Monad m, ToNamedRecord a, DefaultOrdered a) => EncodeOptions -> ConduitT a BS.ByteString m ()  
toNamedDefaultOrderCsv opts = {-# SCC toCsv_p #-} map $ BSL.toStrict . encodeDefaultOrderedByNameWith opts . pure  

The problem is this prints a header per line which I think you allude to in one of your longer comments on #28.

So then... I think I'll be perfectly fine if I can just specify a string to be prepended before all other lines and saw your comment about multiple producers. I came up with this:

runConduit $ sequenceSources [ yieldMany [ Left ()], yieldMany [ Right "a", Right "b" ]]
  .|  concat
  .| (awaitForever $ \x ->
         case x of Left () ->
                     liftIO (putStrLn "hi")
                     Right _ -> yield x)
  .| printC

This only prints out:

hi
Right "a"

I can of course use an IORef to do this, but I'd prefer to make the multiple sources approach work. I think it would be a good addition here as well.

Headers workaround

Hi,
What is the best workaround for creating headers?

Thanks

Silently drops last line if file doesn't end in a new line.

Problem is on line 155.

 await >>= maybe (return ()) (f' . p')

the return () is incorrect as the continuation needs to be passed an empty byte string to get the last value.

containers-0.6.7

Sorry but why a new release with tighter containers bound?
This prevents building in Stackage nightly:

containers-0.6.7 (changelog) is out of bounds for:

• cassava-conduit-0.6.4 (>=0.5.10 && < 0.6). Dom De Re [email protected] @domdere. Used by: library