Comment Feed for Channel 9 - Andrew Kennedy: F# Units of Measure http://ecn.channel9.msdn.com/o9/previewImages/100/488754_100x75.jpg Channel 9 - Andrew Kennedy: F# Units of Measure Floating point values in F# can have associated units of measure, which are typically used to indicate length, volume, mass, and so on. The built-in type float takes an optional unit-of-measure parameter, written in angle brackets, in a similar way that types such as IEnumerable take a type parameter, as in IEnumerable<int>.By using quantities with units, you enable the compiler to verify that arithmetic relationships have the correct units, which helps prevent programming errors like the one that led to NASA's Mars Climate Orbiter being lost in September 1999. This was due to confusion between metric and so-called "English" units of measurement.  The accident could have been prevented if the NASA engineers had been able to annotate their program code with units, and then employed static analysis tools or language-level type-checking to detect and fix any unit errors.Andrew Kennedy is an MSR research scientist who implemented units of measure for F#. What did this involve? How does it work, exactly? What's next? Meet Andrew and learn all about F#'s latest language feature, units of measure.Enjoy. Information sources: http://msdn.com and http://blogs.msdn.com/andrewkennedy/ en Fri, 24 May 2013 18:10:34 GMT Fri, 24 May 2013 18:10:34 GMT Rev9 Re: Andrew Kennedy: F# Units of Measure I was very impressed when seeing units of measure in F# the first time and believe it's a great selling point for the language.

posted by exoteric

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892539560000000 Tue, 22 Sep 2009 22:05:56 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892539560000000 exoteric Re: Andrew Kennedy: F# Units of Measure Thanks, I find this very interesting.  I imagine it can be helpful in many situations. 

posted by Richard.Hein

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892677180000000 Wed, 23 Sep 2009 01:55:18 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892677180000000 Richard.Hein Re: Andrew Kennedy: F# Units of Measure Very interesting ...and deep ... another nice interview Charles!

 

We've seen Don Syme several times on C9 ... its nice to finally see Andrew Kennedy!

 

However ...  the code is completely unreadable!!! Perplexed C'mon cant you guys ever use a larger font? Try 14 please!! Or Just use the new Zoom feature in the VS2010 editor!!

 

I'd like to actually see the code!!!

 

 

posted by keithfl

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892800110000000 Wed, 23 Sep 2009 05:20:11 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892800110000000 keithfl Re: Andrew Kennedy: F# Units of Measure One of my favorite F# features. Thanks for this great interview!

(and unfortunately keithfl is right about the unreadable code Expressionless )

posted by Novox

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892903470000000 Wed, 23 Sep 2009 08:12:27 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633892903470000000 Novox Re: Andrew Kennedy: F# Units of Measure interesting Smiley so this is strictly a compile time feature? its not "generics" really, its sort of compile time generics?

thats the impression i got Smiley

  

--edit--

also, is this just for floats? can a unit be any type? for instance if you have a class Person, could you create a unit of measure for Employee, manager and so on? (just as an example)

posted by aL_

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893037030000000 Wed, 23 Sep 2009 11:55:03 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893037030000000 aL_ Re: Andrew Kennedy: F# Units of Measure Yes, this is strictly a compile-time feature, so units errors get caught at development time, and there is no runtime performance hit.

 

It's for any types you like. Built-in types float, float32, decimal, and int can be parameterized on units, but you can build your own, e.g. vectors, complex numbers, matrices, or whatever. My blog (http://blogs.msdn.com/andrewkennedy) has more info.

posted by akenn

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893116660000000 Wed, 23 Sep 2009 14:07:46 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893116660000000 akenn Re: Andrew Kennedy: F# Units of Measure Ah - sorry about the unreadable code. I had been assuming that the screen would be captured in high-res. A lot of the examples that I used are also discussed on my blog. The Lunar Lander code was written by Phil Trelford but I'll put it back together and post it here shortly.

posted by akenn

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893135930000000 Wed, 23 Sep 2009 14:39:53 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893135930000000 akenn Re: Andrew Kennedy: F# Units of Measure My apologies for the poor resolution of the code demo on-screen. The way that we captured this is the problem. We are working on a solution to this general problem. See, we don't expect interviewees to have to install screen capture software on their laptops in order to record a demo in the studio. That said, we aren't yet sure of a practical solution that also affords least effort on the part of our guests. Working it out.

 

Thank you in advance, Andrew, for sharing the code in project file format. The domo code should be much easier to read in Visual Studio or a text editor Smiley

 

Again, we will work this out.

 

C

posted by Charles

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893169460000000 Wed, 23 Sep 2009 15:35:46 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893169460000000 Charles Re: Andrew Kennedy: F# Units of Measure very cool.. we do alot of physics calculations for measuremnts on lasers so this could be very useful Smiley are you making any large changes in beta2 to this or is the beta1 functionality kinda stable?

posted by aL_

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893176520000000 Wed, 23 Sep 2009 15:47:32 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893176520000000 aL_ Re: Andrew Kennedy: F# Units of Measure Thanks for your reply ... Angel again ... a very interesting feature and a awesome interview!

 

posted by keithfl

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893194410000000 Wed, 23 Sep 2009 16:17:21 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893194410000000 keithfl Re: Andrew Kennedy: F# Units of Measure Measurements in F# is an exciting feature. No doubt about it. I was really impressed when I learned about it being added to the language.

It surely addresses a lot of potential issues with measurement mismatch. 

 

Yet, run time support for measurements still makes a lot of sense.

If you are reading data from external sources at run-time (files, sensors, or web services), you'd still have to implemet all the measurement tracking and conversion yourself. If this can be married to contract somehow, then application would just have to tell the framework that it expects mass to be in kilos, and if input feed turns out to be pounds then conversion would happen under the scene.

 

Another presumably useful feature would be to declare measures off of classes/types. If for example, I'm counting my chicken, I don't want to be able to inadvertently add this to the count of eggs, unless I explicitly coersed chicken and eggs to be "things".

 

Anyhow, compile time support is a very good start.

posted by sokhaty

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893258710000000 Wed, 23 Sep 2009 18:04:31 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893258710000000 sokhaty Re: Andrew Kennedy: F# Units of Measure This is a feature that I have been waiting for.

 

How is the UOM information able to be persited?  If I were serialize an object with UOM would the UOM be included in the XML?

 

Also I read last year that this feature would also automatically take care of some of the unit conversion, say within a calculation.  Is this still possible or will we have to manage the unit conversion ourselves?

 

Awsome stuff!

posted by dPruitt

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893357630000000 Wed, 23 Sep 2009 20:49:23 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893357630000000 dPruitt Re: Andrew Kennedy: F# Units of Measure It's fairly stable. Defining your own overloaded methods on unit-parameterized types is slightly easier, as type inference has been improved. For the product release, there will be a bunch of functions to "cast" into units (e.g. one with type float -> float<'u>) which are intended for interop with non-unit-aware code. (e.g. you might have a numeric library that you want to wrap with a units API.)

posted by akenn

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893782630000000 Thu, 24 Sep 2009 08:37:43 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893782630000000 akenn Re: Andrew Kennedy: F# Units of Measure The units-of-measure information is not persisted, as it is "erased" from types before runtime. (It's a purely static feature.)

 

As for unit conversions, there are no plans for automatic conversions for this release of F#: you must define your own conversion functions.

posted by akenn

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893783820000000 Thu, 24 Sep 2009 08:39:42 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633893783820000000 akenn Re: Andrew Kennedy: F# Units of Measure >> See, we don't expect interviewees to have to install screen capture software on their laptops in order to record a demo in the studio. >> That said, we aren't yet sure of a practical solution that also affords least effort on the part of our guests

Just Remote Desktop into the guest's laptop while recording the screencast on the client-side.

 

Rant: why is Channel9 reliably not working with Firefox browsers?! Impossible to view videos or post replies. Bummer!

posted by Alex O

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633901003410000000 Fri, 02 Oct 2009 17:12:21 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633901003410000000 Alex O Re: Andrew Kennedy: F# Units of Measure Not sure about the FF issues. Can you be more specific? You could also run FF's dev tools and send the script error details Smiley

 

Sorry you having a bad experience. We will look into this.

C

posted by Charles

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633901110410000000 Fri, 02 Oct 2009 20:10:41 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c633901110410000000 Charles Re: Andrew Kennedy: F# Units of Measure Comments open.

C

posted by Charles

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355542840000000 Sat, 12 Mar 2011 19:18:04 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355542840000000 Charles Re: Andrew Kennedy: F# Units of Measure Fermi National Accelerator Laboratory FERMILAB-Conf-98/328 
"Introduction to the SI Library of Unit-Based Computation" by 
Walter E. Brown 
October 1998
Presented at the International Conference on Computing in High Energy Physics (CHEP ’98), Chicago, Illinois, August 31-September 4, 1998
When I got my copy, it was linked from  www.fnal.gov/fermitools
 
 

posted by David Phillip Oster

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355590730000000 Sat, 12 Mar 2011 20:37:53 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355590730000000 David Phillip Oster Re: Andrew Kennedy: F# Units of Measure posted by Vivek

]]> http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355599340000000 Sat, 12 Mar 2011 20:52:14 GMT http://channel9.msdn.com/Blogs/Charles/Andrew-Kennedy-F-Units-of-Measure#c634355599340000000 Vivek