Class: InternalPipeStream

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • initialization
  • queries
  • reading
  • synchronization
  • writing
• Examples

Inheritance:

   Object
   |
   +--Stream
      |
      +--InternalPipeStream

Package:

stx:libbasic2

Category:

Streams

Version:

rev: 1.13 date: 2022/01/14 14:09:31

user: cg

file: InternalPipeStream.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Description:

not useful on its own, but can be used to talk to a vt100
terminal view ...

See example.

copyright
COPYRIGHT (c) 2002 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 new

(comment from inherited method)
report an error - Streams are created using on:-messages

Instance protocol:

 close

if there is any partner waiting at either side of the queue,
tell it that the pipe is no longer active.
(readers will read an EOF condition, writers will get a write error).
Either side may close the internal pipe.

 isOpen

(comment from inherited method)
for compatibility with externalStream:
return true, if this stream is open.

 size

(comment from inherited method)
return the number of elements in the streamed collection.

 contentsSpecies: aCollectionClass

by default, I will return a String of elements, if reading multiple elements.
However, you may change this to eg. an array, if desired

 initialize

(comment from inherited method)
just to ignore initialize to objects which do not need it

 atEnd

(comment from inherited method)
return true if the end of the stream has been reached;
- we do not know here how to do it, it must be redefined in subclass

 contentsSpecies

(comment from inherited method)
this should return the class of which an instance is
returned by the #contents method. Here, Array is returned,
since the abstract Stream-class has no idea of the underlying
collection class.
It is redefined in some subclasses - for example, to return String.

 next

return the next element from the stream (might block until something is written)

 nextAvailableBytes: nMax into: aBuffer startingAt: startIndex

(comment from inherited method)
for compatibility with ExternalStream

 readWaitWithTimeoutMs: millis

suspend the current process, until the receiver
becomes ready for reading or a timeout (in milliseconds) expired.
If data is already available, return immediate.
With nil millis, wait forever.
Return true if a timeout occurred (i.e. false, if data is available).
The other threads are not affected by the wait.

 readWait

(comment from inherited method)
suspend the current process, until the receiver
becomes ready for reading. If data is already available,
return immediately.
The other threads are not affected by the wait.

 writeWaitWithTimeoutMs: timeout

(comment from inherited method)
never have to wait

 nextPut: anObject

write an element (might wakeup readers).
Answer the argument

Usage example(s):

|s| s := InternalPipeStream new. s nextPut:$a. s nextPut:$b. s nextPut:$c.

Examples:

    |p|

    p := InternalPipeStream new.
    [
        10 timesRepeat:[
            p nextPutLine:'hello'.
            Delay waitForSeconds:1.
        ].
    ] fork.

    [
        10 timesRepeat:[
            Transcript showCR:p nextLine
        ].
    ] fork.

    |userInput elizasOutput top terminal|

    userInput    := InternalPipeStream new.
    elizasOutput := InternalPipeStream new.

    top := StandardSystemView new.
    terminal := VT100TerminalView openOnInput: userInput output:elizasOutput in:top.

    top extent:(terminal preferredExtent).
    top label:'The doctor is in'.
    top iconLabel:'doctor'.
    top open.
    top waitUntilVisible.
    top onChangeEvaluate:[:what :aParameter :changedObject | what == #destroyed ifTrue:[userInput close]].

    terminal translateNLToCRNL:true.
    terminal inputTranslateCRToNL:true.
    terminal localEcho:true.

    elizasOutput nextPutLine:'Hi, I am Eliza'.
    elizasOutput nextPutLine:'What is your problem (type end to finish conversation) ?'.
    elizasOutput nextPutLine:''.
    elizasOutput nextPutAll:'>'.

    [top realized] whileTrue:[
        |line answer matchingRule matches what|

        ((userInput readWaitWithTimeout:1) not and:[top realized]) ifTrue:[
            line := userInput nextLine.
            ((line isEmptyOrNil and:[userInput atEnd]) or:[ #('quit' 'exit' 'end' 'bye') includes:line ]) ifTrue:[
                top destroy.
                ^ self
            ].
            (matches := line subExpressionsInRegex:'I am (.+)' caseSensitive:false) size == 1 ifTrue:[
                answer := #( 
                            'Why are you %1?'
                            'What makes you think that you are %1?'
                            'Who told you, that you are %1?'
                          ) atRandom bindWithArguments:matches
            ] ifFalse:[
                answer := 'Tell me more.'.
            ].
            elizasOutput nextPutLine:answer.
            elizasOutput nextPutAll:'>'.
        ].
    ].