Re: Interfaces / data types in E

On 2011-10-06 11:50, Kevin Reid wrote:
> On Oct 6, 2011, at 6:35, Thomas Leonard wrote:
>
>> We've got quite a few methods that take or return maps. e.g.
>>
>> to purchase(customerDetails :Map[String,any]) { ...
>> customerDetails["name"] ... ... if (problem) {
>> notify(customerDetails["email"]) } ... }
>
> When you say "We" do you mean the E project or one of yours?

One of mine.

>> The problem is that it's not obvious from the method signature what
>> keys need to be present. Often someone fails to include a mapping,
>> and the system only fails later in some case where it needed that
>> value.
>>
>> What I think I'd like to do is something like:
>>
>> def CustomerDetails := makeNamedTuple([ "name" =>  String, "email"
>> =>  String, ])
>>
>> ...
>>
>> to purchase(customerDetails :CustomerDetails]) { ...
>> customerDetails["name"] ... }
>
> I think this is a fine guard to have. For consistency with other
> parameterized guards, it should be written NamedTuple[[...]].