pkl: amending #2084
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pkl: amending
#2084
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So pkl has a nice feature, they call it amending:
We are creating
parrotby modifying(bird).What would an equivalent look like in
fastn? We have one thing to worry, we have both mutable objects and non mutable objects. So if you are amending a mutable objects, do you want to retain referencing for the non "amended" fields. We have*$syntax to opt out of linking.We also have to consider if we want to be able to refer to original object, and amend things by saying say
diet = 2 * $this.dietordiet = 2 * $parent.diet(while amending we can say$thisrefers to "parent", or we can be explicit and allow both,$thisand$parent.Amending syntax:
Here we are treating an existing variable
pigeonas the "type" ofparrot, using variable as type means the new variable being created is of the same type as that of referred variable, and is "amending" it.The newly created variable, if it is a mutable variable, this is implicitly clone, and loses referencing to old variable.
If the newly created variable is not mutable, we have explicitly opt in mutable referencing or non mutable referencing by prepending either
$or*$. This forces one to consider mutability impact of referencing another variable.With this: any field of
pigeonif mutated, parrot will follow it:This means things are cloned at construction time.
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