Re: [boost] [GSoC] pipelines questions

Subject: Re: [boost] [GSoC] pipelines questions
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2014-03-01 11:50:46

On 1 Mar 2014 at 16:32, Thaler Benedek wrote:

> pipeline::execution task(
>   pipeline::from(filenames) |
>   pipeline::parallel(read_file | grep_fn | vgrep_fn | sed_fn, 8) |
>   output_queue).run(&thread_pool);

If you're going down the road of adding pipelined i/o, do look into 
proposed Boost.AFIO which already implements chainable asynchronous 
file i/o for you. Should save you a ton of work.

Failing that, Boost.Iostreams also provides a huge amount of 
chainable i/o implementation already written and tested. 
Boost.Iostreams can't do async easily though.

> I can't figure out how to create a segment from "read_file | grep_fn |
> vgrep_fn | sed_fn" without overloading the free function
> operator|(function, function). Is this really we want to do? Shouldn't we
> use pipeline::make() here?

I would look at Google's proposal as merely a suggestion. Microsoft 
have their own proposals for (mis)using the C++ operator syntax as a 
DSL for specifying asynchronous operations. Just because Google 
proposed it doesn't mean it's special.

You're right that overloading global functions is generally to be 
avoided unless you absolutely control the implementation of the types 
entering the global function. I personally think that the 
"Improvements to future<T>" proposal is far safer and much more 
likely to get standardised.

Niall

-- 
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