python vs d

[Paulo Pinto via Digitalmars-d]

On Tuesday, 29 April 2014 at 08:21:04 UTC, John Colvin wrote:
> On Monday, 28 April 2014 at 23:02:03 UTC, bearophile wrote:
>> I think it could be a good idea to add something intermediate 
>> to D: optional strong typing for array indexing. I'd like to 
>> write a DIP on this someday (note that this does not mean I am 
>> suggesting D array indexes to optionally start from values 
>> different from 0. I am referring just to types, and 
>> enumerations are could be not supported).
>>
>> Bye,
>> bearophile
>
> Any reason why this needs language support? I haven't tried it, 
> but I can't see why it can't be trivially done in a library.

Pascal example:

type
   colors = (red, blue, yellow);

var
   pallete : array colors of integer;

begin
  pallete[red] := 4;
end



You want a compiler error if the index is invalid and bounds 
checking when iterating over the enumeration and using it as 
indexes.

Probably possible with some heavy duty compile time 
metaprogramming, not sure about the quality of possible error 
messages and if it would cover all scenarios Pascal and Ada allow 
for.

--
Paulo