# Copyright 2007 Kevin Reid, under the terms of the MIT X license
# found at http://www.opensource.org/licenses/mit-license.html ................

pragma.syntax("0.9")
pragma.enable("call-pattern")

def OutStream :DeepFrozen := <elib:eio.OutStream>
def makeWriterStream :DeepFrozen := <import:org.cubik.cle.io.makeWriterStream>

/** Makes OutStreams which synchronously append to FlexLists or other objects with append/1 and elementType/0 methods. A trivial but frequently occurring use of makeWriterStream. (For closure notification, check the resulting stream's terminates/0.) */
def makeAppendStream implements DeepFrozen, ExitViaHere {
  to run(target) :OutStream {
    # XXX target could be nonnear on construction if we could defer target.elementType(). change makeWriterStream interface?
    return makeWriterStream(List[target.valueType()], E.call, def listWriter {
      to write(chunk) { target.append(chunk) }
      to flush() {}
      to close() {}
      to fail(_) {}
    })
  }
}