Add EffSort, rework ExprInput to use ParserData

[sovdeeth]

Description

This PR supersedes @Pikachu920's #6342 PR to be more generic and extendable. Syntaxes can now implement InputSource to declare themselves as valid sources of input for ExprInput.

This also adds input index as a pattern for ExprInput, which will allow the accessing of a value's index when filtering/sorting a variable list.

Also added is EffSort, an effect for sorting variable lists. This effect allows a custom expression to map the values before sorting, so lists can now be sorted in a somewhat custom manner. The sorting is still done with the natural ordering of the mapped values, so this does not current support custom comparators.
If the custom expression has returns a null value at any point, the sort will be aborted and the list will remain the same, as null values cannot be compared. Alternatively, we could just strip out the invalid values, but I think that's a destructive failure state that could result in users losing valuable data if they make a small mistake.

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Target Minecraft Versions: any
Requirements: none
Related Issues: #6715 #4327

[Pikachu920]

couldnt we do the sorting async?

[sovdeeth]

couldnt we do the sorting async?

pikachu please you're killing me
and yes I think so

[sovdeeth]

couldnt we do the sorting async?

@Pikachu920 we can do the actual sorting asynchronously, but we cannot ensure the expression is safe to evaluate asynchronously, so this would be of limited assistance. Do you think it's still worth adding?

[Pikachu920]

couldnt we do the sorting async?

@Pikachu920 we can do the actual sorting asynchronously, but we cannot ensure the expression is safe to evaluate asynchronously, so this would be of limited assistance. Do you think it's still worth adding?

yes please. I am imagining people will use this for things like "top" listings which might have a lot of elements to sort. I think you have pointed out a larger issue though. anything that uses asynceffect at the moment is probably calling getters async 😖

[APickledWalrus]

super cool. i am wondering if it is a bit confusing to have both a sorting expression and effect? and if we do keep both, does it make sense for ExprFilter to get an effect equivalent?

[APickledWalrus]

should be before return type