Ah, I see, this sound appealing. But I would object this: (I'm speaking of do:, not only to:do:) 1) what the last value mean for unordered collections? 2) for a SequenceableCollection, the behavior is already (someCollection inject: nil into: [:void :each | aBlock value: each]) 3) returning the last value in all implementors of #do: would cost complexification of code and possibly slow down (non clean blocks) Is it really useful? Nicolas 2011/10/16 Stéphane Ducasse <stephane.ducasse@inria.fr>:
for me the last expression of the block.
Stef
Which return value would be useful?
That's not the right question. Â IMO the compiler should answer the same result as the non-inlined one when the return value is asked for. Â Arguably the non-inline version needs to be commented to specify that it returns the value it does (in this case self), and that the compiler's optimiser reflects this.
Agree, but I was wondering what useful object this common answer could be?
Nicolas
2011/10/16 Stéphane Ducasse <stephane.ducasse@inria.fr>:
A friend of mine ask me the following
|result| result := String new. 1 to: 10 do: [:n | result := result, n printString, ' ']. I am trying to do or print this code. It prints 'nil' instead of a collection. Its an example from PBE book. do you know the reason? although this one's working: result := String new. (1 to: 10) do: [:n | result := result, n printString, ' '].
I checked the implementation Interval>>do: aBlock "Evaluate aBlock for each value of the interval. Implementation note: instead of repeatedly incrementing the value aValue := aValue + step. until stop is reached, We prefer to recompute value from start aValue := start + (index * step). This is better for floating points accuracy, while not degrading Integer and Fraction speed too much. Moreover, this is consistent with methods #at: and #size" | aValue index size | index := 0. size := self size. [index < size] whileTrue: [aValue := start + (index * step). index := index + 1. aBlock value: aValue]
Number>>to: stop do: aBlock "Normally compiled in-line, and therefore not overridable. Evaluate aBlock for each element of the interval (self to: stop by: 1)." | nextValue | nextValue := self. [nextValue <= stop] whileTrue: [aBlock value: nextValue. nextValue := nextValue + 1]
any further idea than := value is different from value: Stef
-- best, Eliot