"{ Package: 'squeak:petitparser' }"

ReadStream subclass:#PPStream

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'PetitParser-Core'

!

PPStream comment:'A positional stream implementation used for parsing. It overrides some methods for optimization reasons.'

!

!PPStream methodsFor:'accessing'!

next: anInteger 

	"Answer up to anInteger elements of my collection. Overridden for efficiency."

	| answer endPosition |

	endPosition := position + anInteger min: readLimit.

	answer := collection copyFrom: position + 1 to: endPosition.

	position := endPosition.

	^ answer

!

peek

	"An improved version of peek, that is slightly faster than the built in version."

	^ self atEnd ifFalse: [ collection at: position + 1 ]

!

position: anInteger

	"The receiver does not check for invalid arguments passed to this method, as it is solely used with valid indexes for backtracking."

	position := anInteger

!

uncheckedPeek

	"An unchecked version of peek that throws an error if we try to peek over the end of the stream, even faster than #peek."

	^ collection at: position + 1

! !

!PPStream methodsFor:'converting'!

asPetitStream

	^ self

! !

!PPStream methodsFor:'printing'!

printOn: aStream

	collection isString

		ifFalse: [ ^ super printOn: aStream ].

	aStream

		nextPutAll: (collection copyFrom: 1 to: position);

		nextPutAll: '·';

		nextPutAll: (collection copyFrom: position + 1 to: readLimit)

! !

!PPStream class methodsFor:'documentation'!

version_SVN

    ^ '$Id: PPStream.st,v 1.1 2011-08-18 18:56:17 cg Exp $'

! !