I represent a character by storing its associated ASCII code (extended to 256 codes). My instances are created uniquely, so that all instances of a character ($R, for example) are identical.

	comparing
	< = > hash

	converting
	asCharacter asIRCLowercase asInteger asLowercase asString asSymbol asText asUppercase isoToSqueak squeakToIso to:

	copying
	clone copy deepCopy veryDeepCopyWith:

	object fileIn
	comeFullyUpOnReload: objectForDataStream:

	printing
	hex isLiteral printOn: printOnStream: storeOn:

	testing
	isAlphaNumeric isDigit isLetter isLowercase isSafeForHTTP isSeparator isSpecial isUppercase isVowel tokenish

	class initialization
	initialize

	constants
	alphabet characterTable

	instance creation
	allCharacters digitValue: new separators value:

	accessing	top
	asciiValue Answer the value of the receiver that represents its ascii encoding.
	digitValue Answer 0-9 if the receiver is $0-$9, 10-35 if it is $A-$Z, and < 0 otherwise. This is used to parse literal numbers of radix 2-36.

	comparing	top
	< Answer true if the receiver's value < aCharacter's value.
	= Primitive. Answer true if the receiver and the argument are the same object (have the same object pointer) and false otherwise. Optional. See Object documentation whatIsAPrimitive.
	> Answer true if the receiver's value > aCharacter's value.
	hash Hash is reimplemented because = is implemented.

	converting	top
	asCharacter Answer the receiver itself.
	asIRCLowercase convert to lowercase, using IRC's rules
	asInteger Answer the value of the receiver.
	asLowercase If the receiver is uppercase, answer its matching lowercase Character.
	asString Answer a string that represents the receiver.
	asSymbol Answer a Symbol consisting of the receiver as the only element.
	asText
	asUppercase If the receiver is lowercase, answer its matching uppercase Character.
	isoToSqueak Convert receiver from iso8895-1 (actually CP1252) to mac encoding. Does not do lf/cr conversion! Characters not available in MacRoman encoding have been remapped to their base characters or to $?.
	squeakToIso Convert from mac to iso8895-1 encoding. Does not do lf/cr conversion!
	to: Answer with a collection in ascii order -- $a to: $z

	copying	top
	clone Answer with the receiver, because Characters are unique.
	copy Answer with the receiver because Characters are unique.
	deepCopy Answer with the receiver because Characters are unique.
	veryDeepCopyWith: Return self. I can't be copied.

	object fileIn	top
	comeFullyUpOnReload: Use existing an Character. Don't use the new copy.
	objectForDataStream: I am being collected for inclusion in a segment. Do not include Characters! Let them be in outPointers.

	printing	top
	hex
	isLiteral Answer whether the receiver has a literal text form recognized by the compiler.
	printOn: Append to the argument, aStream, a sequence of characters that identifies the receiver.
	printOnStream:
	storeOn: Character literals are preceded by '$'.

	testing	top
	isAlphaNumeric Answer whether the receiver is a letter or a digit.
	isDigit Answer whether the receiver is a digit.
	isLetter Answer whether the receiver is a letter.
	isLowercase Answer whether the receiver is a lowercase letter. (The old implementation answered whether the receiver is not an uppercase letter.)
	isSafeForHTTP whether a character is 'safe', or needs to be escaped when used, eg, in a URL
	isSeparator Answer whether the receiver is one of the separator characters--space, cr, tab, line feed, or form feed.
	isSpecial Answer whether the receiver is one of the special characters
	isUppercase Answer whether the receiver is an uppercase letter. (The old implementation answered whether the receiver is not a lowercase letter.)
	isVowel Answer whether the receiver is one of the vowels, AEIOU, in upper or lower case.
	tokenish Answer whether the receiver is a valid token-character--letter, digit, or colon.

	accessing untypeable characters	top
	arrowDown
	arrowLeft
	arrowRight
	arrowUp
	backspace Answer the Character representing a backspace.
	cr Answer the Character representing a carriage return.
	delete
	end
	enter Answer the Character representing enter.
	escape Answer the ASCII ESC character
	euro The Euro currency sign, that E with two dashes. The key code is a wild guess
	home
	insert
	lf Answer the Character representing a linefeed.
	linefeed Answer the Character representing a linefeed.
	nbsp non-breakable space.
	newPage Answer the Character representing a form feed.
	pageDown
	pageUp
	space Answer the Character representing a space.
	tab Answer the Character representing a tab.

	class initialization	top
	initialize Create the table of unique Characters. This code is not shown so that the user can not destroy the system by trying to recreate the table.

	constants	top
	alphabet ($a to: $z) as: String
	characterTable Answer the class variable in which unique Characters are stored.

	instance creation	top
	allCharacters
	digitValue: Answer the Character whose digit value is x. For example, answer $9 for x=9, $0 for x=0, $A for x=10, $Z for x=35.
	new Creating new characters is not allowed.
	separators space
	value: Answer the Character whose value is anInteger.