On Fri, 30 Apr 2021, Thiede, Christoph wrote:

> 
> Hi all,
> 
> 
> recently I stumbled upon an extension method for Dictionary which *might* fit well into the Trunk:
> 
> 
> Dictionary >> #at: key ifAbsentPut: startBlock ifPresentPut: nextBlock
> 	"(c) 2020 Basti Kruck und Marcel Taeumel. :-)"	(self includesKey: key) ifFalse: [
> 		^ self at: key put: startBlock value].	^ self
> 		at: key
> 		put: (nextBlock value: (self at: key))
> 
> See https://github.com/hpi-swa/vivide/blob/c4ac5ea562bd563358d52ee41c149a3fbcffd90e/repository/Vivide.package/Dictionary.extension/instance/at.ifAbsentPut.ifPresentPut..st.
> 
> 
> Usage:
> 
> counter := counters at: key ifAbsentPut: [0] ifPresentPut: [:i | i + 1]
> 
> What do you think, should we copy this into the Trunk? Or is it just fine to do something like this instead at the sender side:
> 
> counter := counters at: key put: (counters at: key ifAbsent: [0] ifPresent: [:i | i + 1])

The alternative I would use is the following:

counter := counters at: key put: (counters at: key ifAbsent: [0]) + 1

And I think that is good enough. If wanted to have a special method for 
that case, I would try to look up the key only once.


Levente