Dear Swift community,
while building a framework for BSON I had the following idea.
Here is a snippet of some code I do have in my module:
extension Array where Element == Document.Value {
public func double(at index: Int) -> Double? {
guard self.startIndex <= index && index < self.endIndex else { return
nil }
if case .double(let double) = self[index] {
return double
}
return nil
}
…
}
This function is used to query the array and check if the element at the given
index is of a specific type. Now I would like also to implement a semi-schema
setter.
The problem that I see, is the ugliness of the subscript I’d create.
Currently the code would read nicely let d = array.double(at: 42), but after
change to a subscript the API would look odd array[doubleAt: 42] = 5.0.
Don’t get me wrong here, I also have methods with larger names like public func
scopedJavaScript(at index: Int) -> …. You can easily imagine that such
subscripts would look ugly array[scopedJavaScriptAt: 123] = ….
I propose to align the design of subscript with functions where one could
optionally give subscript a name.
func name(label parameter: Type) -> ReturnType
subscript optionalName(label parameter: Type) -> ReturnType
This change would make my API nice and clean. array.scopedJavaScript[at: 213] =
…
This also might be the opportunity to rethink the labeling rule on subscripts,
but this shall not be the main focus of this pitch.
--
Adrian Zubarev
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