haskell-sort-imports does not recognize multi-line imports

[bos]

If I have an import that spans multiple lines, haskell-sort-imports does two things wrong.

Firstly, it can't tell that it's on a continuation line. If I try sorting imports with the cursor on the line marked CURSOR 1 below, it does nothing.

import Data.Aeson.Encode (encode)
import Data.Aeson.Types        {- CURSOR 2 -}
import Data.Aeson.Parser.Internal (decodeWith, decodeStrictWith,
                                   eitherDecodeWith, eitherDecodeStrictWith,
{- CURSOR 1  -}          jsonEOF, json, jsonEOF', json')
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L

Secondly, if I move the cursor to CURSOR 2 and sort, I get this:

import Data.Aeson.Encode (encode)
import Data.Aeson.Parser.Internal (decodeWith, decodeStrictWith,
import Data.Aeson.Types
                                   eitherDecodeWith, eitherDecodeStrictWith,
                                   jsonEOF, json, jsonEOF', json')
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L

[chrisdone]

This has been bugging me too. Thanks for the example test-case.

Here's a new experimental implementation. It tries to be declaration-based rather than line-based. Should solve both problems described here. Added some test-cases to the test suite (run with make check), too.