# Copyright 2005-2007 Kevin Reid, under the terms of the MIT X license
# found at http://www.opensource.org/licenses/mit-license.html ................

makeAppendStream takes a FlexList or other object providing valueType/0 and append/1 and produces an output stream appending to it.
  
  ? def makeAppendStream :DeepFrozen := <import:org.cubik.cle.io.makeAppendStream>
  # value: <makeAppendStream>

  ? def reporter {
  >   to valueType() { println("valueType"); return int }
  >   match msg { println(msg) }
  > }
  # value: <reporter>
  
  ? def s := makeAppendStream(reporter)
  # stdout: valueType
  #         
  
  # value: -><calling "call" facet>(<listWriter>, ...)

XXX This print syntax reflects its implementation using makeWriterStream, and should be changed. XXX should we print the target list or not? (i.e. revealing existing contents)
  
  ? s.getChunkType()
  # value: List[int]

  ? s.reserve().resolve([10]); "return"
  # stdout: ["append", [[10]]]
  #         
  
  # value: "return"

Delivery occurs synchronously with the resolve message.
  
Flushing does not notify the target.

  ? s.flush()
  
Closure affects the stream, but does not notify the target.
  
  ? s.reserve().resolve(null)
  
  ? [s.reserve()]
  # value: [null]

  ? def s := makeAppendStream(reporter)
  > s.reserve().resolve(Ref.broken("boing"))
  > [s.reserve()]
  # stdout: valueType
  #         
  
  # value: [<ref broken by problem: boing>]