On Thursday, 30 June 2016 at 17:08:45 UTC, Jonathan Marler wrote:
Is there a way to have an associative array of const values? I
thought it would have been:
const(T)[K] map;
map[x] = y;
but the second line gives Error: cannot modify const
expression. I would think that the const(T)[K] would behave
similarly to const(T)[], where you can modify the array, just
not the individual elements, but associative arrays don't seem
to have the same semantics. Is there a way to achieve these
semantics with an associative array?
It is possible to initialize the array with a AA literal as
const(int)[string] aa = [ "1": 1, "2": 2 ];
but AAs don't have opIndexAssign etc.
The reasonable things you do to const(T)[] is shorten it or
reassign it completely.
For an AA, this is removing elements or adding new ones. While
the first is without problems, the problem is how to determine if
aa["1"] = 1 is a (legal) initialization or (illegal) reassignment
of a const(T). Unfortunately, there is no function to add
key-value-pairs that throws an Error if the key is already there
or else reinitializes the value.
