Status: FixedWaitingToBePharoed Owner: stephane.ducasse Labels: Type-Squeak New issue 3234 by stephane.ducasse: fold: reduce: Merge http://code.google.com/p/pharo/issues/detail?id=3234 I imagine that reduce: and fold: are not the same in pharo so we should pay attention. Name: Collections-ul.403 Author: ul Time: 7 November 2010, 1:55:55.898 am UUID: 7f81b384-8004-cd44-81e0-9b294d999c8a Ancestors: Collections-ul.402 - merged Collection's #fold: and #reduce: (it's a bit faster than the original versions :)) Item was changed: ----- Method: Collection>>fold: (in category 'enumerating') ----- fold: binaryBlock "Evaluate the block with the first two elements of the receiver, then with the result of the first evaluation and the next element, and so on. Answer the result of the final evaluation. If the receiver is empty, raise an error. If the receiver has a single element, answer that element." "#('if' 'it' 'is' 'to' 'be' 'it' 'is' 'up' 'to' 'me') fold: [:a :b | a, ' ', b]" + ^self reduce: binaryBlock! - | firstValue nextValue | - firstValue := nextValue := Object new. "something that can't be in the receiver" - self do: - [:each | - nextValue := firstValue == nextValue - ifTrue: [each] - ifFalse: [binaryBlock value: nextValue value: each]]. - ^nextValue == firstValue - ifTrue: [self errorEmptyCollection] - ifFalse: [nextValue]! Item was changed: ----- Method: Collection>>reduce: (in category 'enumerating') ----- reduce: binaryBlock "Apply the argument, binaryBlock cumulatively to the elements of the receiver. For sequenceable collections the elements will be used in order, for unordered collections the order is unspecified." | first nextValue | - self emptyCheck. first := true. + self do: [ :each | + first + ifTrue: [ nextValue := each. first := false ] + ifFalse: [ nextValue := binaryBlock value: nextValue value: each ] ]. + first ifTrue: [ self errorEmptyCollection ]. - self do:[:each| - first ifTrue:[nextValue := each. first := false] - ifFalse:[nextValue := binaryBlock value: nextValue value: each]]. ^nextValue!