On Thursday, January 25, 2018, Tom Lane <
tgl@sss.pgh.pa.us> wrote:
The documentation currently says
The CONSTANT option prevents the variable from being assigned to
after initialization, so that its value will remain constant for
the duration of the block.
While we don't really have the concept of mutable types other languages do. Maybe just saying "from being assigned or mutated after initialization" would suffice.
I don't see a desirable way to reinforce that the y in arr[y] is unenforced documentation - in the code or docs - beyond what is already done. That distinction doesn't usually come up and for those where it does the docs will probably be an after-the-fact confirmation of observed behavior.
David J.