Re: [Boost-users] [ICL] Can't use an enum as map value

Subject: Re: [Boost-users] [ICL] Can't use an enum as map value
From: Krzysztof Czainski (1czajnik_at_[hidden])
Date: 2014-03-19 08:18:39

2014-03-19 13:11 GMT+01:00 Oodini <svdbg____at_[hidden]>:

> Hello,
>
> I declared an interval_map :
>
> interval_map<uint16_t, SomeEnumType> myMap;
>
> Later, I do :
>
> SomeEnumType enumValue = SOME_ENUM_VALUE;
> myMap.add(std::make_pair(disxrete_interval<uint16_t>(10,17),
> SOME_ENUM_VALUE);
>
> But that doesn't compile.
>
> It seems that ICL wants the += operator must eb defined for value type
> (why ???).
>
> What can I do ?
>

Hi,

If I remember correctly, you need to supply a combiner. The default
combiner uses +=.

A combiner produces a new value for overlapping intervals. Consider
(pseudocode):

myMap.add( [10,17), SOME_ENUM_VALUE );
myMap.add( [16,18), OTHER_ENUM_VALUE );

The combiner decides, what should be the value in [16,17). In this case,
tries to += the OTHER_ENUM_VALUE to the existing SOME_ENUM_VALUE.

HTH,
Kris