I scan a string or text, picking out Smalltalk syntactic tokens. I look one character ahead. I put each token found into the instance variable, token, and its type (a Symbol) into the variable, tokenType. At the end of the input stream, I pretend to see an endless sequence of special characters called doits.

	expression types
	advance checkpoint nextLiteral revertToCheckpoint: scanLitVec scanLitWord scanStringStruct scanToken step

	initialize-release
	initScanner scan:

	multi-character scans
	xBinary xColon xDelimiter xDigit xDollar xDoubleQuote xLetter xLitQuote xSingleQuote

	public access
	scanFieldNames: scanMessageParts: scanStringStruct: scanTokens:

	instance creation
	new

	testing
	isLiteralSymbol:

	error handling	top
	notify: Refer to the comment in Object|notify:.
	offEnd: Parser overrides this

	expression types	top
	advance
	checkpoint Return a copy of all changeable state. See revertToCheckpoint:
	nextLiteral Same as advance, but -4 comes back as a number instead of two tokens
	revertToCheckpoint: Revert to the state when checkpoint was made.
	scanLitVec
	scanLitWord Accumulate keywords and asSymbol the result.
	scanStringStruct
	scanToken
	step

	initialize-release	top
	initScanner
	scan: Bind the input stream, fill the character buffers and first token buffer.

	multi-character scans	top
	xBinary
	xColon Allow := for assignment by converting to #_
	xDelimiter Ignore blanks, etc.
	xDigit Form a number.
	xDollar Form a Character literal.
	xDoubleQuote Collect a comment.
	xLetter Form a word or keyword.
	xLitQuote Symbols and vectors: #(1 (4 5) 2 3) #ifTrue:ifFalse: #'abc'.
	xSingleQuote String.

	public access	top
	scanFieldNames: Answer an Array of Strings that are the identifiers in the input string, stringOrArray. If passed an Array, just answer with that Array, i.e., assume it has already been scanned.
	scanMessageParts: Return an array of the form (comment keyword comment arg comment keyword comment arg comment) for the message pattern of this method. Courtesy of Ted Kaehler, June 1999
	scanStringStruct: The input is a string whose elements are identifiers and parenthesized groups of identifiers. Answer an array reflecting that structure, representing each identifier by an uninterned string.
	scanTokens: Answer an Array that has been tokenized as though the input text, textOrString, had appeared between the array delimitors #( and ) in a Smalltalk literal expression.

	class initialization	top
	initialize Object initialize

	instance creation	top
	new Answer a new instance of the receiver (which is a class) with no indexable variables. Fail if the class is indexable.

	testing	top
	isLiteralSymbol: Test whether a symbol can be stored as # followed by its characters. Symbols created internally with asSymbol may not have this property, e.g. '3' asSymbol.