Re: [boost] utility class: lazy data type

Subject: Re: [boost] utility class: lazy data type
From: Olaf Peter (ope-devel_at_[hidden])
Date: 2009-01-19 09:19:36

> template<class T>
> class lazy
> {
> public:
>     explicit lazy(function<T ()> fetch)
>         : _fetch(fetch)
>     {
>     }
> 
>     T get()
>     {
>         if (!_cached)
>             _cached = _fetch();
>         return _cached.get();
>     }
> 
> private:
>     optional<T> _cached;
>     function<T ()> _fetch;
> };

I miss a set function; e.g. from parser you get a string which is
interpreted as a number and used, later changed/rewritten and saved
(e.g. by use of spririt's Qi & Karma) as string again. Maybe another
pattern for this use case is appropriate?

Regards,
Olaf