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Hosted by Ahuka on 2019-08-16 is flagged as Clean and released under a CC-BY-SA license.
Tags: Health, Medicine, Evidence, Science, Studies.
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Series: Health and Healthcare | Comments (0)
We take the ideas we have developed over the previous episodes and use them to evaluate a a study I found online. These are things anyone can do with just a little work on Google, and the payoff is to have a good idea of whether or not you are looking at a quality study
In this series I cover how I listen to podcasts and how the process has change over the years. This episode badly covers the console audio player moc.
Link to HPR 2112 (Home Server) episode mentioned in this podcast
http://hackerpublicradio.org/eps.php?id=2112
My first MP3 player was a Jelly Bean shaped MP3 player apparently known as an S1 MP3 player
https://en.wikipedia.org/wiki/S1_MP3_player
Sansa Clip info on wikipedia
http://en.wikipedia.org/wiki/Sansa_Clip#Sansa_Clip
Raspberry Pi
https://en.wikipedia.org/wiki/Raspberry_Pi
Music On Console (MOC) is an ncurses-based console audio player for Linux/UNIX
Here is a link to information about moc on wikipedia
https://en.wikipedia.org/wiki/Music_on_Console
sudo apt-get install mocType classes are Haskell’s way of doing ad hoc polymorphics or overloading. They are used to defined set of functions that can operate more than one specific type of data.
In Haskell there’s no default equality, it has to be defined.
There’s two parts to the puzzle. First is type class Eq that comes with the standard library and defines function signatures for equality and non-equality comparisons. There’s type parameter a in the definition, which is filled by user when they define instance of Eq for their data. In that instance definition, a is filled with concrete type.
class Eq a where
(==) :: a -> a -> Bool
(/=) :: a -> a -> Bool
x /= y = not (x == y)Definition above can be read as “class Eq a that has two functions with following signatures and implementations”. In other words, given two a, this function determines are they equal or not (thus Bool as return type). /= is defined in terms of ==, so it’s enough to define one and you get other one for free. But you can still define both if you’re so included (maybe some optimization case).
If we define our own Size type, like below, we can compare sizes:
data Size = Small | Medium | Large
deriving (Show, Read)
instance Eq Size where
Small == Small = True
Medium == Medium = True
Large == Large = True
_ == _ = FalseAnd here’s couple example comparisons.
> Small == Small
True
> Large /= Large
FalseWriting these by hand is both tedious and error prone, so we usually use automatic derivation for them. Note how the second line now reads deriving (Show, Read, Eq).
data Size = Small | Medium | Large
deriving (Show, Read, Eq)There can be hierarchy between type classes, meaning one requires presence of another. Common example is Ord, which is used to order data.
class Eq a => Ord a where
compare :: a -> a -> Ordering
(<) :: a -> a -> Bool
(>=) :: a -> a -> Bool
(>) :: a -> a -> Bool
(<=) :: a -> a -> Bool
max :: a -> a -> a
min :: a -> a -> aThis definition can be read as “class Ord a, where a has instance of Eq, with pile of functions as follows”. Ord has default implementation for quite many of these, in terms of others, so it’s enough to implement either compare or <=.
For our Size, instance of Ord could be defined as:
instance Ord Size where
Small <= _ = True
Medium <= Small = False
Medium <= _ = True
Large <= Large = True
Large <= _ = FalseThere’s lots and lots of type classes in standard library:
Num for numeric operationsIntegral for integer numbersFloating for floating numbersShow for turning data into stringsRead for turning strings to dataEnum for sequentially ordered types (these can be enumerated)Bounded for things with upper and lower boundType classes allow you to write really generic code. Following is contrived example using Ord and Show:
check :: (Ord a, Show a) => a -> a -> String
check a b =
case compare a b of
LT ->
show a ++ " is smaller than " ++ show b
GT ->
show a ++ " is greater than " ++ show b
EQ ->
show a ++ " and " ++ show b ++ " are equal"Check takes two parameters that are same type and that type has to have Ord and Show instances. Ord is for ordering and Show is for turning data into string (handy for displaying it). The end result is string telling result of comparison. Below is some examples of usage. Note how our function can handle different types of data: Size, Int and [Int].
> check Medium Small
"Medium is greater than Small"
> check Small Large
"Small is smaller than Large"
> check 7 3
"7 is greater than 3"
> check [1, 2] [1, 1, 1]
"[1, 2] is greater than [1, 1, 1]"There are many extensions to type classes that add more behaviour. These aren’t part of standard Haskell, but can be enabled with a pragma definition or compiler flag. They can be somewhat more complicated to use, have special cases that need careful consideration, but offer interesting options.
Thank you for listening. Question, comments and feedback welcome. Best way to catch me nowadays is either by email or in fediverse, where I’m tuturto@mastodon.social.
Hosted by Dave Morriss on 2019-08-13 is flagged as Explicit and released under a CC-BY-SA license.
Tags: zenity,Bash scripting,pdmenu,GTK+.
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Series: Bash Scripting | Comments (0)
I use pdmenu a lot to help me do work on my main desktop PC. I did an HPR show on pdmenu on 13 December 2017 and the author Joey Hess responded in show 2459.
In the intervening time I have also integrated Zenity into my menus. This is a GUI tool which generates a number of different pop-up windows known as dialogs, which can display information, or into which information can be typed. The capabilities provided by pdmenu are a little too basic to enable me to do what I need to do.
I thought it might be of interest to show some examples of how I use this tool with pdmenu.
I have provided detailed notes as usual for this episode, and these can be viewed here.
Hosted by Windigo on 2019-08-12 is flagged as Explicit and released under a CC-BY-SA license.
Tags: food,cooking.
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Comments (2)
This recipe has been heavily adapted from one I received from Hello Fresh - credit where credit's due!
Ingredients:
Note: If these metric measurements seem crazy, they probably are.
https://sites.google.com/site/recycledrecumbents/ez-clone-drawings
One of the donors
Dross
The gold
First cut
Cutting tubes
Workmate
Frame 2 parts
Frame 1 parts
Hosted by Jon Kulp on 2019-08-08 is flagged as Clean and released under a CC-BY-SA license.
Tags: Recording, Audio, Tape, Cassette, Recording Devices, Tape Speeds, Electronics, Repair.
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I found a pretty cool little handheld cassette recorder at Salvation Army Thrift Store for 99 cents yesterday. It was non-functioning. I was able to get it working again by 1. cleaning corrosion from battery compartment; 2. replacing the nasty gooey belt; 3. repairing the battery compartment, which had a broken-off spring for one of the battery's negative connections. The most interesting feature of the device is that it has a variable-speed knob for playback at higher speed. I demonstrate this in the podcast.
For more information, have a look at BoardGameGeek: https://boardgamegeek.com/boardgame/71721/space-hulk-death-angel-card-game
In this episode I give some shoe lace tips
Shoe Laces Ted Talk with over 6.5 million views
https://www.ted.com/talks/terry_moore_how_to_tie_your_shoes?language=en
Some further info on the shoe lace knot from the wonderful wikipedia site
https://en.wikipedia.org/wiki/Shoelace_knot
Fast tie shoe laces recommended for anyone in a hurry
https://www.amazon.co.uk/Gritin-Elastic-Laces-Black-Reflective/dp/B07GYM9RC8/ref=cts_sp_3_vtp
Hosted by HPR Volunteers on 2019-08-05 is flagged as Explicit and released under a CC-BY-SA license.
Tags: Community News.
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Series: HPR Community News | Comments (0)
Welcome to our new host:
mightbemike.
These are comments which have been made during the past month, either to shows released during the month or to past shows. There are 13 comments in total.
There are 2 comments on 2 previous shows:
There are 11 comments on 4 of this month's shows:
Policy decisions surrounding HPR are taken by the community as a whole. This discussion takes place on the Mail List which is open to all HPR listeners and contributors. The discussions are open and available on the HPR server under Mailman.
The threaded discussions this month can be found here:
http://hackerpublicradio.org/pipermail/hpr_hackerpublicradio.org/2019-July/thread.htmlWith the kind permission of LWN.net we are linking to The LWN.net Community Calendar.
Quoting the site:
This is the LWN.net community event calendar, where we track events of interest to people using and developing Linux and free software. Clicking on individual events will take you to the appropriate web page.
From Susan Rose, Social Media Manager for OLF:
Dear Open Source Fans, Students and Professionals:
The 2019 Ohio LinuxFest is looking for presentations on Friday and Saturday, November 1 and 2. Please visit the CFP page https://ohiolinux.org/call-for-presentations/ for full details about submitting a proposal. The deadline is Friday, August 17, but the sooner you can submit a talk, the better.
Started in 2003, the Ohio LinuxFest https://ohiolinux.org/ is an annual grassroots conference in Columbus, Ohio dedicated to open access for all. Presentations relating to any free and open source software, not just Linux, are welcome. Areas where we’ve had talks in the past include networking, system administration, development, and community building. A preliminary pdf brochure is attached.
Our audience consists of people at all skill levels. Prior speaking experience is a plus, although we do try to provide opportunities for first-time speakers. If you have any questions, please contact us at speakers@ohiolinux.org. We look forward to hearing from you! Thank you for your kind attention and for sharing.
The PDF Brochure mentioned is available at http://hackerpublicradio.org/eps/hpr2871/olf2019.pdf.
We upload all HPR shows to the Internet Archive (archive.org). Shows downloaded via the HPR RSS feeds actually come from there, though they are also available on the HPR site.
Unfortunately, on Friday July 12th the archive.org copy of the show hpr2855 :: HPR NYE Show 2018-2019 part 6 was found to have been truncated and to consist only of the introduction and final part; no actual content.
The problem was detected during the morning of Friday and was rectified during the afternoon (UK time). The RSS feeds were adjusted to ensure the show was re-downloaded and all podcatchers should have received the correct version the next time they checked the feed.
Thanks to the following contributor for sending in updates in the past month: Dave Morriss
Over the period tags and/or summaries have been added to 11 shows which were without them.
If you would like to contribute to the tag/summary project visit the summary page at https://hackerpublicradio.org/report_missing_tags.php and follow the instructions there.
Get a full list of all our shows.