"
COPYRIGHT (c) 1994 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:libbasic' }"
Stream subclass:#PeekableStream
instanceVariableNames:''
classVariableNames:'ErrorDuringFileInSignal CurrentFileInDirectoryQuerySignal
CurrentSourceContainerQuery'
poolDictionaries:''
category:'Streams'
!
!PeekableStream class methodsFor:'documentation'!
copyright
"
COPYRIGHT (c) 1994 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
"
abstract superclass for all Stream which support read-ahead
(i.e. peeking) of one element.
Concrete subclasses must implement a peek method.
[author:]
Claus Gittinger
"
! !
!PeekableStream class methodsFor:'initialization'!
initialize
"setup the signal used to handle errors during fileIn"
ErrorDuringFileInSignal isNil ifTrue:[
ErrorDuringFileInSignal := Error newSignalMayProceed:true.
ErrorDuringFileInSignal nameClass:self message:#errorDuringFileInSignal.
ErrorDuringFileInSignal notifierString:'error during fileIn'.
]
"
self initialize
"
"Modified: / 23-10-2006 / 16:34:41 / cg"
! !
!PeekableStream class methodsFor:'Signal constants'!
currentFileInDirectoryQuerySignal
"return the querySignal, which can be used to ask for the current directory
during a fileIn (that is the directory where the filed-in file resides),
and in a fileBrowsers doIt.
Using this, allows for the loaded code or doIts to ask for the fileBrowsers
current directory, by asking this querySignal (which is nice sometimes)."
CurrentFileInDirectoryQuerySignal isNil ifTrue:[
CurrentFileInDirectoryQuerySignal := QuerySignal new.
CurrentFileInDirectoryQuerySignal nameClass:self message:#currentFileInDirectoryQuerySignal.
CurrentFileInDirectoryQuerySignal notifierString:'query for current directory when filing in'.
CurrentFileInDirectoryQuerySignal handlerBlock:[:ex | ex proceedWith:Filename currentDirectory].
].
^ CurrentFileInDirectoryQuerySignal
"Modified: / 23-10-2006 / 16:34:37 / cg"
!
currentSourceContainerQuery
"return the querySignal, which can be used to ask for the current source container filename
during a fileIn
Using this, allows for the loaded code to remember the classes file name."
CurrentSourceContainerQuery isNil ifTrue:[
CurrentSourceContainerQuery := QuerySignal new.
CurrentSourceContainerQuery nameClass:self message:#currentClassFilenameQuery.
CurrentSourceContainerQuery notifierString:'query for current sorce container name when filing in'.
CurrentSourceContainerQuery handlerBlock:[:ex | ex proceedWith:nil].
].
^ CurrentSourceContainerQuery
"Modified: / 23-10-2006 / 16:32:49 / cg"
! !
!PeekableStream class methodsFor:'queries'!
currentFileInDirectory
"during a fileIn (if a script), the script can ask for the current directory"
^ self currentFileInDirectoryQuerySignal query
"Modified: / 23-10-2006 / 16:34:47 / cg"
!
currentSourceContainer
"during a fileIn (if a script), the script can ask for the current filename"
^ self currentSourceContainerQuery query
"Modified: / 23-10-2006 / 16:33:40 / cg"
! !
!PeekableStream methodsFor:'chunk input/output'!
nextChunk
"return the next chunk, i.e. all characters up to the next
exclamation mark. Within the chunk, exclamation marks have to be doubled,
they are undoubled here.
Except for primitive code, in which doubling is not needed (allowed).
This exception was added to make it easier to edit primitive code with
external editors. However, this means, that other Smalltalks cannot always
read chunks containing primitive code
- but that doesn't really matter, since C-primitives are an ST/X feature anyway."
|theString chunkSeparator newString done thisChar nextChar
atBeginOfLine inPrimitive hasCR hasLF
index "{ Class:SmallInteger }"
currSize "{ Class:SmallInteger }" |
chunkSeparator := ChunkSeparator.
currSize := 500.
theString := String new:currSize.
self skipSeparators.
thisChar := self nextOrNil.
index := 0.
done := false.
atBeginOfLine := true.
inPrimitive := false.
hasCR := hasLF := false.
[done not and:[thisChar notNil]] whileTrue:[
((index + 2) <= currSize) ifFalse:[
newString := String new:(currSize * 2).
newString replaceFrom:1 to:currSize with:theString.
currSize := currSize * 2.
theString := newString
].
"match primitive only at beginning of line
(ExternalStream>>#nextChunk did this, although stc allows primitive to start anywhere)"
(atBeginOfLine and:[thisChar == $%]) ifTrue:[
nextChar := self peekOrNil.
(nextChar == ${ ) ifTrue:[
inPrimitive := true.
index := index + 1.
theString at:index put:thisChar.
thisChar := self next
] ifFalse:[
(nextChar == $} ) ifTrue:[
inPrimitive := false.
index := index + 1.
theString at:index put:thisChar.
thisChar := self next
]
]
] ifFalse:[
"chunk can not end in primitive code"
(inPrimitive not and:[thisChar == chunkSeparator]) ifTrue:[
(self peekOrNil == chunkSeparator) ifTrue:[
"double chunkSeparator, make single"
self next.
] ifFalse:[
"single chunkSeparator: end of chunk"
done := true.
].
].
].
done ifFalse:[
"now map CR LF to LF (ExternalStream>>#nextChunk did this)"
atBeginOfLine := false.
thisChar == Character return ifTrue:[
self peekOrNil == Character lf ifTrue:[
self next.
thisChar := Character lf.
hasLF := true.
] ifFalse:[
"CR without LF"
hasCR := true.
].
atBeginOfLine := true.
] ifFalse:[thisChar == Character lf ifTrue:[
hasLF := true.
atBeginOfLine := true.
]].
index := index + 1.
theString at:index put:thisChar.
thisChar := self nextOrNil.
].
].
(index == 0) ifTrue:[^ ''].
theString := theString copyTo:index.
(hasCR and:[hasLF not]) ifTrue:[
"map all CR in a CR only file to NL (ExternalStream>>#nextChunk did this)"
theString replaceAll:Character cr with:Character nl.
].
^ theString
! !
!PeekableStream methodsFor:'fileIn'!
fileIn
"file in from the receiver, i.e. read chunks and evaluate them -
return the value of the last chunk."
|notifiedLoader lastValue|
SourceFileLoader notNil ifTrue:[
notifiedLoader := SourceFileLoader on:self.
].
Class nameSpaceQuerySignal handle:[:ex |
ex proceedWith:Smalltalk
] do:[
lastValue := self fileInNotifying:notifiedLoader passChunk:true.
].
^ lastValue.
!
fileInBinary
"file in from the receiver, i.e. read binary stored classes and/or objects.
Return the last object."
|bos obj|
bos := BinaryObjectStorage onOld:self.
Class nameSpaceQuerySignal
answer:Smalltalk
do:[
[self atEnd] whileFalse:[
obj := bos next.
]
].
bos close.
^ obj
"Created: / 13.11.2001 / 10:12:30 / cg"
"Modified: / 13.11.2001 / 10:14:04 / cg"
! !
!PeekableStream methodsFor:'positioning'!
skipAny:skipCollection
"skip all characters included in the argument-set.
returns the next peeked element or nil, if the end-of-stream was reached."
|nextOne|
nextOne := self peekOrNil.
[nextOne notNil and:[skipCollection includes:nextOne]] whileTrue:[
self next.
nextOne := self peekOrNil
].
^ nextOne
"
|s skipChars|
s := ReadStream on:'some numbers1234with\in other99 stuff' withCRs.
skipChars := 'abcdefghijklmnopqrstuvwxyz\ ' withCRs.
s skipAny:skipChars.
Transcript showCR:(Integer readFrom:s).
s skipAny:skipChars.
Transcript showCR:(Integer readFrom:s).
"
!
skipSeparators
"skip all whitespace; returns the next peeked element or
nil, if the end-of-stream was reached.
The streams elements should be characters.
Notice: compare this method to skipSpaces"
|nextOne|
nextOne := self peekOrNil.
[nextOne notNil and:[nextOne isSeparator]] whileTrue:[
self next.
nextOne := self peekOrNil
].
^ nextOne
"
|s|
s := ReadStream on:'one two\three' withCRs.
s skipSeparators.
Transcript showCR:(s nextWord).
s skipSeparators.
Transcript showCR:(s nextWord).
s skipSeparators.
Transcript showCR:(s next displayString).
"
!
skipSeparatorsExceptCR
"skip all whitespace except carriage return; returns the
next peeked element or nil, if the end-of-stream was reached.
The streams elements should be characters.
Notice: compare this method to skipSpaces and skipSeparators"
|nextOne|
nextOne := self peekOrNil.
[nextOne notNil
and:[nextOne isSeparator
and:[nextOne ~~ Character cr]]] whileTrue:[
self next.
nextOne := self peekOrNil
].
^ nextOne
!
skipSpaces
"skip all spaces; returns the next peeked element or
nil, if the end-of-stream was reached.
The streams elements should be characters.
Notice: this one skips only spaces (i.e. no cr, tabs etc)
usually, skipSeparators is what you want."
|nextOne|
nextOne := self peekOrNil.
[nextOne notNil and:[nextOne == Character space]] whileTrue:[
self next.
nextOne := self peekOrNil
].
^ nextOne
"
|s|
s := ReadStream on:'one two\three' withCRs.
s skipSpaces.
Transcript showCR:(s nextWord).
s skipSpaces.
Transcript showCR:(s nextWord).
s skipSpaces.
Transcript showCR:(s next displayString).
"
! !
!PeekableStream methodsFor:'private fileIn'!
basicFileInNotifying:someone passChunk:passChunk
"central method to file in from the receiver, i.e. read chunks and evaluate them -
return the value of the last chunk.
Someone (which is usually some codeView) is notified of errors."
^(EncodedStream decodedStreamFor:self) basicFileInNotifying:someone passChunk:passChunk
"Modified: / 10-09-1999 / 16:54:01 / stefan"
"Modified: / 16-11-2001 / 16:21:28 / cg"
"Modified: / 25-03-2013 / 22:57:55 / Jan Vrany <jan.vrany@fit.cvut.cz>"
!
fileInNextChunkNotifying:someone
"read next chunk, evaluate it and return the result;
someone (which is usually some codeView) is notified of errors.
Filein is done as follows:
read a chunk
if it started with an excla, evaluate it, and let the resulting object
fileIn more chunks.
This is a nice trick, since the methodsFor: expression evaluates to
a ClassCategoryReader which reads and compiles chunks for its class.
However, other than methodsFor expressions are possible - you can
(in theory) create readers for any syntax.
"
^ self fileInNextChunkNotifying:someone passChunk:false
!
fileInNextChunkNotifying:someone passChunk:passChunk
"read next chunk, evaluate it and return the result;
someone (which is usually some codeView) is notified of errors.
Filein is done as follows:
read a chunk
if it started with an excla, evaluate it, and let the resulting object
fileIn more chunks.
This is a nice trick, since the methodsFor: expression evaluates to
a ClassCategoryReader which reads and compiles chunks for its class.
However, other than methodsFor expressions are possible - you can
(in theory) create readers for any syntax.
"
^ self fileInNextChunkNotifying:someone passChunk:passChunk silent:nil
!
fileInNextChunkNotifying:someone passChunk:passChunk silent:beSilent
"read next chunk, evaluate it and return the result;
someone (which is usually some codeView) is notified of errors.
Filein is done as follows:
read a chunk
if it started with an excla, evaluate it, and let the resulting object
fileIn more chunks.
This is a nice trick, since the methodsFor: expression evaluates to
a ClassCategoryReader which reads and compiles chunks for its class.
However, other than methodsFor expressions are possible - you can
(in theory) create readers for any syntax.
"
|aString sawExcla rslt done compiler|
self skipSeparators.
self atEnd ifFalse:[
sawExcla := self peekFor:(self class chunkSeparator).
aString := self nextChunk.
"/
"/ handle empty chunks;
"/ this allows for Squeak code to be filedIn
"/
[aString size == 0
and:[self atEnd not]] whileTrue:[
aString := self nextChunk.
].
aString size ~~ 0 ifTrue:[
passChunk ifTrue:[
someone notNil ifTrue:[someone source:aString]
].
compiler := Smalltalk::Compiler new.
compiler allowUndeclaredVariables:false.
sawExcla ifFalse:[
"/ class definition chunks, etc., which are simply evaluated
rslt := compiler evaluate:aString notifying:someone.
] ifTrue:[
"/ methodsFor chunks, etc., which generate a reader
Smalltalk::Compiler emptySourceNotificationSignal handle:[:ex |
^ nil
] do:[
rslt := compiler
evaluate:aString
notifying:someone
compile:false.
].
"
usually, the above chunk consists of some methodsFor:-expression
in this case, the returned value is a ClassCategoryReader,
which is used to load & compile the methods ...
"
(rslt isNil or:[rslt == #Error]) ifTrue:[
"
however, if that was nil (i.e. some error), we skip chunks
up to the next empty chunk.
"
Transcript showCR:'skipping chunks ...'.
done := false.
[done] whileFalse:[
aString := self nextChunk.
done := (aString size == 0).
]
] ifFalse:[
rslt := rslt
fileInFrom:self
notifying:someone
passChunk:passChunk
single:false
silent:beSilent
]
]
]
].
^ rslt
"Modified: / 05-02-2011 / 10:06:57 / cg"
!
fileInNotifying:notifiedLoader passChunk:passChunk
"central method to file in from the receiver, i.e. read chunks and evaluate them -
return the value of the last chunk.
Someone (which is usually some codeView) is notified of errors."
^ self basicFileInNotifying:notifiedLoader passChunk:passChunk.
!
fileInXMLNotifying:someone passChunk:passChunk
"filein an XML source file (format as in campSmalltalk DTD)"
| builder parser|
(XML isNil or:[XML::SourceNodeBuilder isNil or:[XML::XMLParser isNil]]) ifTrue:[
Smalltalk loadPackage:'stx:goodies/xml/vw'.
(XML isNil or:[XML::SourceNodeBuilder isNil or:[XML::XMLParser isNil]]) ifTrue:[
self error:'Could not load XML package(s) from ''stx:goodies/xml/vw'''.
]
].
builder := XML::SourceNodeBuilder new.
parser := XML::XMLParser on:self.
parser builder:builder.
parser validate:false.
parser scanDocument.
"/ self halt.
! !
!PeekableStream methodsFor:'reading'!
nextDecimalInteger
"read the next integer in radix 10. Does NOT skip initial whitespace.
The streams elements should be characters.
Be careful - this method returns 0 if not posiioned on a digit intitially
or if the end of the stream is encountered."
|nextOne value|
nextOne := self peekOrNil.
value := 0.
[nextOne notNil and:[nextOne isDigitRadix:10]] whileTrue:[
value := (value * 10) + nextOne digitValue.
self next.
nextOne := self peekOrNil
].
^ value
"
|s|
s := '1234 5678' readStream.
s nextDecimalInteger.
"
"
|s|
s := '1234 5678' readStream.
s nextDecimalInteger.
s skipSpaces.
s nextDecimalInteger.
"
!
nextDelimited:terminator
"return the contents of the receiver, up to the next terminator character.
Doubled terminators indicate an embedded terminator character.
For example: 'this '' was a quote'.
Start postioned before the initial terminator."
| out ch |
out := WriteStream on: (String uninitializedNew: 1000).
self atEnd ifTrue: [^ ''].
self next == terminator ifFalse: [self skip: -1]. "absorb initial terminator"
[(ch := self next) == nil] whileFalse: [
(ch == terminator) ifTrue: [
self peek == terminator ifFalse: [
^ out contents "terminator is not doubled; we're done!!"
].
self next. "skip doubled terminator"
].
out nextPut: ch.
].
^ out contents
"
('*foo bar baz* more foo' readStream nextDelimited:$*)
('*foo bar **baz***' readStream nextDelimited:$*)
"
!
nextPeek
"advance to next element and return the peeked element"
self next.
^ self peek
!
nextUpTo:anObject
"read a collection of all objects up-to anObject and return these
elements, but excluding anObject.
The next read operation will return anObject.
If anObject is not encountered, all elements up to the end are read
and returned, and the stream is positioned at the end.
Compare this with #upTo: which positions behind anObject"
|answerStream element|
answerStream := WriteStream on:(self contentsSpecies new).
[self atEnd] whileFalse:[
element := self peek.
(element = anObject) ifTrue: [
^ answerStream contents
].
answerStream nextPut:element.
self next.
].
^ answerStream contents
"
|s|
s := ReadStream on:#(1 2 3 4 5 6 7 8).
Transcript showCR:(s nextUpTo:4).
Transcript showCR:s next
|s|
s := ReadStream on:#(1 2 3 4 5 6 7 8).
Transcript showCR:(s upTo:4).
Transcript showCR:s next
|s|
s := ReadStream on:#(1 2 3 4 5 6 7 8).
Transcript showCR:(s nextUpTo:9).
Transcript showCR:s next
|s|
s := ReadStream on:#(1 2 3 4 5 6 7 8).
Transcript showCR:(s upTo:9).
Transcript showCR:s next
"
"Created: 24.1.1997 / 14:08:35 / cg"
"Modified: 24.1.1997 / 14:09:49 / cg"
!
peek
"return the next element of the stream without advancing (i.e.
the following send of next will return this element again.)
- we do not know here how to do it, it must be redefined in subclass"
^ self subclassResponsibility
!
peekFor:anObject
"if the next-to-be-read object is equal to the argument, anObject, read it
and return true. Otherwise, leave the receiver unaffected and return false."
self peek = anObject ifTrue:[
self nextOrNil.
^ true
].
^ false
"
#() readStream peekFor:nil
#() readStream signalAtEnd:true; peekFor:nil
#(nil) readStream peekFor:nil
"
!
peekOrNil
"like #peek, this returns the next readAhead element, if available.
However, unlike #peek, this does not raise an atEnd-query signal - even
if handled. Instead, nil is returned immediately."
self atEnd ifTrue:[^ nil].
^ self peek
"Created: / 5.3.1998 / 02:56:49 / cg"
"Modified: / 5.3.1998 / 13:45:07 / cg"
!
throughAnyForWhich:checkBlock
"read & return a collection of all objects up-to and including
the elements for which checkBlock returns true.
(i.e. read until checkBlock returns false on an element)
If no such element is encountered, all elements up to the end are read
and returned."
|answerStream element|
answerStream := WriteStream on:(self contentsSpecies new).
[self atEnd] whileFalse:[
element := self peek.
(checkBlock value:element) ifFalse:[
^ answerStream contents
].
answerStream nextPut:element.
self next.
].
^ answerStream contents
"
|s|
s := ReadStream on:#(1 2 3 4 5 6 7 8).
Transcript showCR:(s throughAny:#(3 4 5)).
Transcript showCR:s next
|s|
s := ReadStream on:'hello world, this is some text'.
Transcript showCR:(s throughAnyForWhich:[:ch | ch isSeparator not]).
Transcript showCR:(s throughAnyForWhich:[:ch | ch isSeparator not]).
Transcript showCR:s upToEnd.
"
"Modified: / 11.1.1998 / 15:28:04 / cg"
!
upToMatching:aBlock
"Return the next elements up to but not including the next element
for which aBlock returns true.
The next read will return that matching element."
|answerStream element|
answerStream := WriteStream on:(self contentsSpecies new).
[self atEnd] whileFalse: [
element := self peek.
(aBlock value:element) ifTrue: [^ answerStream contents].
answerStream nextPut:element.
self next.
].
^ answerStream contents
"
'hello world' readStream upToMatching:[:c | c isSeparator].
"
"
|s|
s := 'hello world' readStream.
s upToMatching:[:c | c isSeparator].
s upToEnd
"
"Modified: 26.2.1997 / 12:20:57 / cg"
!
upToSeparator
"Return the next elements up to but not including the next separator.
The next read will return the separator.
If no separator is encountered, the contents up to the end is returned.
The elements are supposed to understand #isSeparator
(i.e. the receiver is supposed to be a character-stream)."
^ self upToMatching:[:ch | ch isSeparator]
"
'hello world' readStream upToSeparator
'helloworld' readStream upToSeparator
'helloworld' readStream upToSeparator
'' readStream upToSeparator
|s|
s := 'hello world' readStream.
s upToSeparator.
s upToEnd
"
"Modified: 4.1.1997 / 23:38:05 / cg"
! !
!PeekableStream methodsFor:'reading-strings'!
nextAlphaNumericWord
"read the next word (i.e. up to non letter-or-digit).
Return a string containing those characters.
Any leading non-alphaNumeric chars are skipped."
|s c|
"first: skip white space and other garbage, leave first character in c"
[
c := self nextOrNil.
c isNil ifTrue:[
"end of stream"
^ nil.
].
c isLetterOrDigit
] whileFalse.
"second: get the alphanumeric word"
s := WriteStream on:(String new:128).
[
s nextPut:c.
c := self peekOrNil.
(c notNil and:[c isLetterOrDigit]) ifTrue:[
self next.
true.
] ifFalse:[
false.
]
] whileTrue.
^ s contents.
"Use UnicodString in the examples, to avoid the optimization in ReadStream for Strings"
"
|s|
s := 'hello world 1234 foo1 foo2' asUnicodeString readStream.
[s atEnd] whileFalse:[
Transcript showCR:(s nextAlphaNumericWord).
].
"
"
|s|
s := 'hello +++ #world ###123###abc### 1234 foo1 foo2++++' asUnicodeString readStream.
[s atEnd] whileFalse:[
Transcript showCR:(s nextAlphaNumericWord).
].
"
"Modified: 15.5.1996 / 17:51:42 / cg"
!
nextMatching:matchBlock1 thenMatching:matchBlock2
"read the next word. The first character must match matchBlock1,
remaining characters must match matchBlock2.
Return a string containing those characters."
|s c|
self atEnd ifTrue:[^ nil].
(matchBlock1 value:self peek) ifFalse:[^ nil].
s := self next asString.
[self atEnd not
and:[matchBlock2 value:(c := self peek)]] whileTrue:[
s := s copyWith:c.
self next
].
s size == 0 ifTrue:[^ nil].
^ s.
"
|s|
s := 'hello_world_1234 foo1 foo2' readStream.
s nextMatching:[:c | c isLetter] thenMatching:[:c | c isLetterOrDigit or:[c == $_]].
"
!
nextSymbol
"read the next selector-symbol (i.e. up to non letter-or-digit).
Return a string containing those characters.
Any leading non-alphaNumeric chars are skipped."
|symbol c symbolStream|
[self atEnd
or:[(c := self peek) isLetterOrDigit]] whileFalse:[
self next
].
self atEnd ifTrue:[^ nil].
symbolStream := '' writeStream.
[self atEnd not
and:[(c := self peek) isLetterOrDigit or:[c == $:]]] whileTrue:[
symbolStream nextPut:c.
self next
].
symbol := symbolStream contents.
symbol size == 0 ifTrue:[^ nil].
^ symbol.
"
|s|
s := 'hello: world 1234 foo1 foo2:' readStream.
[s atEnd] whileFalse:[
Transcript showCR:(s nextSymbol).
].
"
"
|s|
s := 'hello +++ #world ###123###abc### 1234 foo1 foo2' readStream.
[s atEnd] whileFalse:[
Transcript showCR:(s nextAlphaNumericWord).
].
"
"Modified: 15.5.1996 / 17:51:42 / cg"
! !
!PeekableStream class methodsFor:'documentation'!
version
^ '$Header: /cvs/stx/stx/libbasic/PeekableStream.st,v 1.42 2013-03-19 13:15:55 stefan Exp $'
!
version_CVS
^ '$Header: /cvs/stx/stx/libbasic/PeekableStream.st,v 1.42 2013-03-19 13:15:55 stefan Exp $'
!
version_HG
^ '$Changeset: <not expanded> $'
! !
PeekableStream initialize!