[squeak-dev] Dictionary >> #at:ifAbsentPut:ifPresentPut:

Tobias Pape Das.Linux at gmx.de
Fri Apr 30 17:05:54 UTC 2021


Hi



> On 30. Apr 2021, at 18:36, Thiede, Christoph <Christoph.Thiede at student.hpi.uni-potsdam.de> 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])
> 
> Also, I'm not sure about the order of arguments.

I find it a bit too specific for trunk.
It's quite an edge case...

-t



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