Dr. Dobb's is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Channels ▼

Christopher Diggins

Dr. Dobb's Bloggers

Implicit Concurrency from Sources, Filters, and Sinks

September 27, 2009

One of my areas of investigation is how to allow a language to exploit implied concurrency. One way is by expressing algorithms in terms of source, filters, and sinks.  

If shell scripting has taught me anything, it is that many sophisticated algorithms can be expressed in terms of a source, filter, and a sink. The source produces data, the filter transforms the data, and the sink consumes the data.

Expressing these algorithms in shell languages is dirt easy, but requires a ton of boilerplate in many languages (e.g. C++, C#, Java). In Heron I not only want to make it easy to write these kinds of programs, but I also want to allow the compiler to take advantage of the implicit concurrency automatically. 

I am planning to introduce an associative operator "|>" which means take the data from a source and pump it into a filter or sink.  The expression "source |> filter" would generate a new source, while "source |> sink" would generate a new sink. 

Consider then the example of "A |> B |> C |> D". Rather than waiting for each item to pump through the entire pipeline, in theory we can have multiple items in the pipeline at a single time. I just haven't worked out an efficient implementation yet. 

Right now, I am looking into an implementation that assigns a thread to each stage of the pipeline, and shares results with the next stage via a queue. The big problem I have to solve, is how to do it safely but as efficiently as possible. 

I'll keep you posted as my solution develops, but in the meantime I'd love to hear your suggestions. 

Related Reading

More Insights

Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.