raise(SessionError(VFSIstrings.SR.couldNotFindFsiExe fsiRegistryPath))

letnewLine= Event<_>()

letbuffer= System.Text.StringBuilder(1024)

letbyteBuffer= Array.zeroCreate128

letencoding= System.Text.Encoding.UTF8

letdecoder= encoding.GetDecoder()

letasync0= async.Return0

letmaxCharsInBuffer= encoding.GetMaxCharCount byteBuffer.Length

Array.zeroCreate maxCharsInBuffer

if pos>= buffer.Lengththen max(buffer.Length-1)0// exit and point to the last char

letc= buffer.[pos]

if c='\r'|| c='\n'then

letline= buffer.ToString(0, pos)

newLine.Trigger line

if c='\r'&&(pos+1)< buffer.Length&& buffer.[pos+1]='\n'then pos+2else pos+1

buffer.Remove(0, deletePos)|> ignore

findLinesInBuffer0

findLinesInBuffer(pos+1)

reader.BaseStream.AsyncRead(byteBuffer,0, byteBuffer.Length)

|:? IOException-> async0

if bytesRead<>0then

letcharsRead= decoder.GetChars(byteBuffer,0, bytesRead, charBuffer,0)

buffer.Append(charBuffer,0, charsRead)|> ignore

letnewPos= findLinesInBuffer pos

return! read newPos

Async.StartImmediate(read0)

newLine.Publish

letprocInfo=new ProcessStartInfo()

letfsiPath= determineFsiPath()

letoutW,outE=lete=new Event<_>()in e.Trigger, e.Publish

leterrW,errE=lete=new Event<_>()in e.Trigger, e.Publish

letexitE=(cmdProcess.Exited|> Observable.map(fun x-> x))// this gives the event the F# "standard" event type IEvent<'a> rather than IEvent<_,_>

cmdProcess.OutputDataReceived|> catchAll|> Observable.add(fun data->

outW(data.Data));

cmdProcess.ErrorDataReceived|> catchAll|> Observable.add(fun data-> errW(data.Data));

let_= cmdProcess.Start()

cmdProcess.BeginOutputReadLine();

cmdProcess.BeginErrorReadLine();

readLinesAsync cmdProcess.StandardOutput|> catchAll|> Observable.add(fun data->

outW(data));

readLinesAsync cmdProcess.StandardError|> catchAll|> Observable.add(fun data-> errW(data));