briot
commented
5 years ago +1 for making this a general facility applicable to user-defined types. I would have liked to use something similar for GNATCOLL.Strings.
But perhaps it would be better to think of this in a more general context where a range is an actual object that can be passed around. C++ has just gained that feature (for prior-art), as well as languages like D and python.
As a use case, say I have a Sum function that receives an array of Float and adds them up.
If I want to use it on a subset of the array, I would pass Arr (4..7). The same cannot be done with the Ada containers. I have a Sum for a vector, I have to write a second version of Sum that also receives the beginning and started indexes, and likely a third one that receives start and end as cursors. It would be nicer if I could write a Sum that receives a vector range as a parameter, and would automatically also accept a vector itself as a synonym for "full range".
Syntactically, ranges would be a different kind of types, built either by functions or via the ".." operator.
(just a rough idea, this would obviously need more thoughts and formalization)
sttaft
This proposal seems in the same spirit as the approved "user defined literals" AIs and container aggregates.
It seems like a sensible addition pending any potential conflicts an Ada-lawyer might identify : )