Re: [boost] Interest check: memoization

Subject: Re: [boost] Interest check: memoization
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-01-24 23:32:27

AMDG

James Porter wrote:
> After hacking around with some simple dynamic programming, it occurred 
> to me that it should be possible to write a simple class template to 
> handle memoization of functions. With the changes in C++0x that help 
> solve the forwarding problem, writing a generic memoizer should be 
> fairly straightforward. (Or so I thought!)
>
> Comments and criticisms are welcome. If there's interest, I will - of 
> course - work on a version that supports the current C++ standard.

The implementation of less in upgradable_tuple_inner doesn't look quite 
right.

        return get(as_ref) < rhs.get(rhs_as_ref)
            || tail.less(as_ref,rhs.tail,rhs_as_ref);

Shouldn't this be

        return get(as_ref) < rhs.get(rhs_as_ref)
            || (!(rhs.get(rhs_as_ref) < get(as_ref)) && 
tail.less(as_ref,rhs.tail,rhs_as_ref));

Also, upgradable_tuple_inner::upgrade isn't exception safe.

Fairly minor and maybe I shouldn't be worrying about them at this stage, 
but still...

In Christ,
Steven Watanabe