"

 COPYRIGHT (c) 2009 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.

"

"{ Package: 'stx:libbasic2' }"

"{ NameSpace: Smalltalk }"

PeekableStream subclass:#CollectingReadStream

	instanceVariableNames:'collectBlock inStream'

	classVariableNames:''

	poolDictionaries:''

	category:'Streams-Misc'

!

!CollectingReadStream class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 2009 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.

"

!

documentation

"

    A stream which evaluates collectBlock for every element

    read from an underlying stream, providing the result from

    the evaluation as read-elements.

    Useful to process a readStream, for tracing or diverting to another

    processing stage.

    [Author:]

        Claus Gittinger

"

!

examples

"

                                                            [exBegin]

    |s|

    s := CollectingReadStream 

            on:#(1 2 3 4 5 6 7 8) readStream

            collecting:[:each | each squared].

    s upToEnd  

                                                            [exEnd]

                                                            [exBegin]

    |s|

    s := (#(1 2 3 4 5 6 7 8) readStream 

            selecting:[:n | n odd])

                collecting:[:n | n squared].

    s upToEnd    

                                                            [exEnd]

"

! !

!CollectingReadStream class methodsFor:'instance creation'!

diverting:aStream to:anotherStream

    ^ self on:aStream collecting:[:el | anotherStream nextPut:el. el].

    "

     |s|

     s := CollectingReadStream 

            diverting:#(1 2 3 4 5 6 7 8) readStream

            to:Transcript.

     s upToEnd  

    "

!

on:aStream collecting:aBlock

    ^ self basicNew on:aStream collecting:aBlock

    "

     |s|

     s := CollectingReadStream 

            on:#(1 2 3 4 5 6 7 8) readStream

            collecting:[:each | each squared].

     s upToEnd  

    "

! !

!CollectingReadStream methodsFor:'instance creation'!

on:aStream collecting:aBlock

    inStream := aStream.

    collectBlock := aBlock.

! !

!CollectingReadStream methodsFor:'queries'!

atEnd

    ^ inStream atEnd

!

contentsSpecies

    "return a class of which instances will be returned, when

     parts of the collection are asked for. 

     (see upTo-kind of methods in Stream)"

    ^ inStream contentsSpecies.

! !

!CollectingReadStream methodsFor:'stream protocol'!

next

    inStream atEnd ifTrue:[

        ^ self pastEndRead

    ].

    ^ collectBlock value:(inStream next)

!

nextOrNil

    |ch|

    ch := inStream nextOrNil.

    ch notNil ifTrue:[

        collectBlock value:ch

    ].

    ^ ch

    "Created: / 26-10-2011 / 17:29:01 / cg"

!

nextPeek

    self next.

    ^ self peek

    "Created: / 26-10-2011 / 17:25:16 / cg"

!

peek

    ^ inStream peek

    "Created: / 26-10-2011 / 17:24:59 / cg"

!

peekOrNil

    ^ inStream peekOrNil

    "Created: / 26-10-2011 / 17:25:32 / cg"

!

position

    ^ inStream position

    "Created: / 26-10-2011 / 17:25:08 / cg"

!

position0Based

    <resource: #obsolete>

    ^ inStream position

    "Created: / 26-10-2011 / 17:23:56 / cg"

!

position1Based

    <resource: #obsolete>

    ^ inStream position + 1

    "Created: / 26-10-2011 / 17:22:42 / cg"

!

readStream

    ^ self

    "Created: / 26-10-2011 / 17:25:43 / cg"

! !

!CollectingReadStream class methodsFor:'documentation'!

version_CVS

    ^ '$Header$'

! !