I see threeWayCompareTo: aString "Do a three-way comparison between the receiver and anotherObject, returning -1 if self < anotherObject 0 if self = anotherObject 1 if self > anotherObject This assumes a total order in accordance with the mathematical law of trichotomy. See also: http://en.wikipedia.org/wiki/Three-way_comparison" ^ (self compare: self with: aString collated: AsciiOrder) - 2 And I thought that we got a new primitive returning -101 directly Is it not the case? Stef String>>compare: string1 with: string2 collated: order "'abc' = 'abc' asWideString >>> true" "'abc' asWideString = 'abc' >>> true" "(ByteArray with: 97 with: 0 with: 0 with: 0) asString ~= 'a000' asWideString >>> true" "('abc' sameAs: 'aBc' asWideString) >>> true" "('aBc' asWideString sameAs: 'abc') >>> true" "('a000' asWideString ~= (ByteArray with: 97 with: 0 with: 0 with: 0) asString) >>> true" "((ByteArray with: 97 with: 0 with: 0 with: 0) asString sameAs: 'Abcd' asWideString) >>> false" "('a000' asWideString sameAs: (ByteArray with: 97 with: 0 with: 0 with: 0) asString) >>> false" (string1 isByteString and: [string2 isByteString]) ifTrue: [ ^ ByteString compare: string1 with: string2 collated: order]. "Primitive does not fail properly right now" ^ String compare: string1 with: string2 collated: order ByteString>>compare: string1 with: string2 collated: order "Return 1, 2 or 3, if string1 is <, =, or > string2, with the collating order of characters given by the order array." | len1 len2 c1 c2 | <primitive: 'primitiveCompareString' module: 'MiscPrimitivePlugin'> <var: #string1 declareC: 'unsigned char *string1'> <var: #string2 declareC: 'unsigned char *string2'> <var: #order declareC: 'unsigned char *order'> len1 := string1 size. len2 := string2 size. 1 to: (len1 min: len2) do: [:i | c1 := order at: (string1 basicAt: i) + 1. c2 := order at: (string2 basicAt: i) + 1. c1 = c2 ifFalse: [c1 < c2 ifTrue: [^ 1] ifFalse: [^ 3]]]. len1 = len2 ifTrue: [^ 2]. len1 < len2 ifTrue: [^ 1] ifFalse: [^ 3].