Re: [boost] Monad (was: Re: [Boost-users] [afio] Formal review of Boost.AFIO)

Subject: Re: [boost] Monad (was: Re: [Boost-users] [afio] Formal review of Boost.AFIO)
From: Sam Kellett (samkellett_at_[hidden])
Date: 2015-08-24 19:30:19

On 24 August 2015 at 21:18, Niall Douglas <s_sourceforge_at_[hidden]> wrote:

> On 24 Aug 2015 at 18:59, Sam Kellett wrote:
>
> > i've played with the idea in my head for the past half an hour and i
> think
> > i would quite like boost::monad to be maybe a few customisation points:
> > bind, return, fail, even >> and >>= (although i would imagine
> associativity
> > and precedence would get in the way of the last two) that your own
> > monadic-like classes could specialise and then use as first class monads.
> > this is maybe getting a bit off topic now so i'll stop.
>
> Monad has all those items you mention. See
> https://ned14.github.io/boost.monad/singletonboost_1_1monad_1_1basic__
> monad.html under the section "Functional programming extensions
> (optional)".
>
> You also get to customise them to your heart's content via the policy
> class infrastructure. After all, basic_future<> which subclasses
> basic_monad<> implements binds as continuations.
>

that does look good, don't get me wrong. but would i be able to use it to,
say, provide monadic options to std::list? or io ala haskell? because if
not i would wonder why not simply because it's called 'monad'.

what if i wanted to use the >> operator on a boost::optional, could i do
that with your monad type?

i'm sure i'm being dense, but i couldn't find an example of the policy
infrastructure so i couldn't answer those questions myself.