Past Meetup

[Scala] Implicits and Iteratees

This Meetup is past

57 people went

Location image of event venue


Bill Venners and Dick Wall are in town thanks to Dominion Marine Media, who've been kind enough to make this meetup possible.

Implicit Conversions to Implicit Parameters in ScalaTest 2.0

In this talk, Bill Venners will tell the story of the journey from a design that leaned towards implicit conversions in ScalaTest 1.0 to one that emphasizes implicit parameters in ScalaTest and ScalaUtils 2.0.

Using primarily demos in the Scala REPL, Bill will show you several use cases and applications of implicit parameters that will help you understand the tradeoffs between implicit conversions and parameters and how to take advantage of implicit parameters in your own designs.

Bill Venners is the lead developer and designer of ScalaTest, an open source testing tool for Scala and Java developers, and coauthor with Martin Odersky and Lex Spoon of the book, Programming in Scala. Iteratees and Real Life

Iteratees and Real Life

This talk will look at the problem of processing data sets that are too large to deal with in memory using functional approaches rather than the hadoop style map/reduce approach that is more common. Iteratees turn the problem of processing large or even potentially infinite data sets inside out compared to iterative approaches, allowing you to string together a workflow or "machine" that represents the entire end to end operation first, all purely functional, and then fire the individual arguments (inputs) into it when the result is forced.

The benefits are real: totally flat memory usage, ability to handle endless streams of data, even more efficiency for some operations (for example, large files are accessed only once, never re-parsed) and when things go right, everything is rosy.

When things go wrong, life isn't quite so rosy. Confusing results, difficulty debugging, and mistakes in the implementations of key pieces in the workflow make for a sometimes lengthy and confusing debugging session.

We will look at what life is like down in the trenches with iteratees, in a code-heavy talk with examples in scalaz streams.


Dick Wall, a Java programmer for more than 15 years, began writing Java applets using Symantec Cafe on a Mac. He has worked with large simulations of energy distribution systems and with geographical information systems, and was an Android advocate at Google. Currently, he does research into human genetics using Scala at Locus Development. He also partners with Bill Venners at Escalate Software, where he provides Scala training and consulting, and currently he works almost exclusively with Scala. In addition, he is the creator and co-host of the popular Java Posse podcast, and he founded the Bay Area Scala Enthusiasts (BASE) in Silicon Valley.


• 6:00PM Doors are open, feel free to mingle

• 6:30 Presentations start

• 8:00 Off to a nearby watering hole for a pint, food, and/or breakout discussions

Getting There

By transit it's near the Burrard street Skytrain (check Google Maps or the Translink site for your particular case) that will get you there. For the drivers, it's downtown be prepared to pay, especially after 6.

How to Contact Us / Re Comments

Please note any comments you add to this event (below) will be e-mailed to all members of the group. We're trying to avoid spamming the list, so please do not use comments for jokes, job postings, requests for help programming something or anything else off topic. If you have questions or need to contact us, use the 'contact us' link on the left. Thanks!