-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | J in Haskell
--   
--   Haskell library for calling J
@package j
@version 0.1.0.0


-- | Marshal a limited subset of J arrays into Repa arrays.
--   
--   <h1>Tutorial</h1>
--   
--   Suppose we wish to perform linear regression. In J we could do:
--   
--   <pre>
--   xs := 1 2 3
--   ys := 2 4 6
--   
--   reg_result =: ys %. xs ^/ i.2
--   </pre>
--   
--   To do this with Haskell data:
--   
--   <pre>
--   do
--      jenv &lt;- <a>jinit</a> <a>libLinux</a>
--   
--      let hsArr0 = R.fromListUnboxed (R.ix1 3) [1.0,2.0,3.0]
--          hsArr1 = R.fromListUnboxed (R.ix1 3) [2.0,4.0,6.0]
--          jArr0 = <a>JDoubleArr</a> $ R.copyS $ R.map (realToFrac :: Double -&gt; CDouble) hsArr0
--          jArr1 = <a>JDoubleArr</a> $ R.copyS $ R.map (realToFrac :: Double -&gt; CDouble) hsArr1
--   
--      <a>setJData</a> jenv "xs" jArr0
--      <a>setJData</a> jenv "ys" jArr1
--   
--      <a>bsDispatch</a> jenv "reg_result =: ys %. xs ^/ i.2"
--   
--      <a>JDoubleArr</a> res &lt;- <a>getJData</a> jenv "reg_result"
--      R.toList res
--   </pre>
--   
--   There are three steps to do the calculation, plus one to get a J
--   environment.
--   
--   <ol>
--   <li>Use <a>jinit</a> with the appropriate file path for your
--   platform</li>
--   <li>Marshal Haskell values and send them to the J environment. To do
--   so, we use <a>setJData</a>, which takes a <a>JData</a> containing a
--   repa array or a string.</li>
--   <li>Perform calculations within the J environment. Here, we use
--   <a>bsDispatch</a> to compute some results and assign them within
--   J</li>
--   <li>Marshal J values back to Haskell. We use <a>getJData</a>
--   again.</li>
--   </ol>
--   
--   Since marshaling data between J and Haskell is expensive, it's best to
--   do as much computation as possible in J.
--   
--   <h1>FFI</h1>
--   
--   If you want to marshal data yourself, say to use a <tt>Vector</tt>,
--   look at <a>JEnv</a>.
module Language.J
data JEnv
JEnv :: Ptr J -> JDoType -> JGetMType -> JGetRType -> JSetAType -> JEnv
[context] :: JEnv -> Ptr J
[evaluator] :: JEnv -> JDoType
[reader] :: JEnv -> JGetMType
[out] :: JEnv -> JGetRType
[setter] :: JEnv -> JSetAType

-- | Get a J environment
--   
--   Passing the resultant <a>JEnv</a> between threads can cause unexpected
--   bugs.
jinit :: RawFilePath -> IO JEnv

-- | Expected <a>RawFilePath</a> to the library on a Linux machine.
libLinux :: RawFilePath

-- | Expected <a>RawFilePath</a> to the library on Mac.
libMac :: JVersion -> RawFilePath

-- | Send some J code to the environment.
bsDispatch :: JEnv -> ByteString -> IO ()

-- | Read last output
--   
--   For debugging
bsOut :: JEnv -> IO ByteString
type JVersion = [Int]

-- | J data backed by repa array
data JData sh
JIntArr :: !Array F sh CInt -> JData sh
JDoubleArr :: !Array F sh CDouble -> JData sh
JBoolArr :: !Array F sh CChar -> JData sh
JString :: !ByteString -> JData sh

-- | &lt;math&gt; in the array size
getJData :: Shape sh => JEnv -> ByteString -> IO (JData sh)

-- | &lt;math&gt; in the array size
setJData :: Shape sh => JEnv -> ByteString -> JData sh -> IO CInt

-- | Abstract context
data J
type JDoType = Ptr J -> CString -> IO CInt
type JGetMType = Ptr J -> CString -> Ptr CLLong -> Ptr CLLong -> Ptr (Ptr CLLong) -> Ptr (Ptr CChar) -> IO CInt
type JGetRType = Ptr J -> IO CString
type JSetAType = Ptr J -> CLLong -> CString -> CLLong -> Ptr () -> IO CInt