# News aggregator

### Decoding UTF-8 with Parser Combinators

### http-client: proxy environment variable support

### The GHC Team: GHC Weekly News - 2015/01/19

Hi *,

It's time for some more GHC news! The GHC 7.10 release is closing in, which has been the primary place we're focusing our attention. In particular, we're hoping RC2 will be Real Soon Now.

Some notes from the past GHC HQ meetings this week:

- GHC 7.10 is still rolling along smoothly, and it's expected that RC2 will be cut this Friday, January 23rd. Austin sent out an email about this to ghc-devs, so we can hopefully get all the necessary fixes in.

- Our status page for GHC 7.10 lists all the current bullet points and tickets we hope to address: https://ghc.haskell.org/trac/ghc/wiki/Status/GHC-7.10.1

- Currently, GHC HQ isn't planning on focusing many cycles on any GHC 7.10 tickets that aren't
**highest priority**. We're otherwise going to fix things as we see fit, at our leisure - but a highest priority bug is a showstopper for us. This means if you have something you consider a showstopper for the next release, you should bump the priority on the ticket and yell at us!

- We otherwise think everything looks pretty smooth for 7.10.1 RC2 - our libraries are updated, and most of the currently queued patches (with a few minor exceptions) are done and merged.

Some notes from the mailing list include:

- Austin announced the GHC 7.10.1 RC2 cutoff, which will be on
**Friday the 23rd**. https://www.haskell.org/pipermail/ghc-devs/2015-January/008026.html

- Austin has alerted everyone that soon, Phabricator will run all builds with ./validate --slow, which will increase the time taken for most builds, but will catch a wider array of bugs in commits and submitted patches - there are many cases the default ./validate script still doesn't catch. https://www.haskell.org/pipermail/ghc-devs/2015-January/008030.html

- Johan Tibell asked about some clarifications for the HsBang datatype inside GHC. In response, Simon came back with some clarifications, comments, and refactorings, which greatly helped Johan. ttps://www.haskell.org/pipermail/ghc-devs/2015-January/007905.html

- Jens Petersen announced a Fedora Copr repo for GHC 7.8.4: https://www.haskell.org/pipermail/ghc-devs/2015-January/007978.html

- Richard Eisenberg had a question about the vectoriser: can we disable it? DPH seems to have stagnated a bit recently, bringing into question the necessity of keeping it on. There hasn't been anything done yet, but it looks like the build will get lighter, with a few more modules soon: https://www.haskell.org/pipermail/ghc-devs/2015-January/007986.html

- Ben Gamari has an interesting email about trying to optimize bytestring, but he hit a snag with small literals being floated out causing very poor assembly results. Hopefully Simon (or anyone!) can follow up soon with some help: https://www.haskell.org/pipermail/ghc-devs/2015-January/007997.html

- Konrad Gądek asks: why does it seem the GHC API is slower at calling native code than a compiled executable is? Konrad asks as this issue of performance is particularly important for their work. https://www.haskell.org/pipermail/ghc-devs/2015-January/007990.html

- Jan Stolarek has a simple question: what English spelling do we aim for in GHC? It seems that while GHC supports an assortment of British and American english syntactic literals (e.g. SPECIALIZE and SPECIALISE), the compiler sports an assortment of British/American identifiers on its own! https://www.haskell.org/pipermail/ghc-devs/2015-January/007999.html

- Luis Gabriel has a question about modifying the compiler's profiling output, particularly adding a new CCS (Cost Centre Structure) field. He's hit a bug it seems, and is looking for help with his patch. https://www.haskell.org/pipermail/ghc-devs/2015-January/008015.html

Closed tickets the past few weeks include: #9966, #9904, #9969, #9972, #9934, #9967, #9875, #9900, #9973, #9890, #5821, #9984, #9997, #9998, #9971, #10000, #10002, #9243, #9889, #9384, #8624, #9922, #9878, #9999, #9957, #7298, and #9836.

### Project euler problem #3: comparing my solution to the official.

I'm just looking for some insight and feedback. I came up with this answer for problem 3; find the largest prime factor of 600851475143.

sqrtInt n = round $ sqrt $ fromIntegral n factors n = filter (\x -> n `rem` x == 0) [2..(sqrtInt n)] prime n = null $ factors n main = do let number = 600851475143 let primes = filter prime $ factors number print (last primes)How does this stack up against the official answer given in the Haskell wiki? My answer makes a lot more sense to me coming from an imperative programming background and the magic in the official answer kind of scares me. I am curious, how does my answer compare in terms of efficiency and why?

primes = 2 : filter (null . tail . primeFactors) [3,5..] primeFactors n = factor n primes where factor n (p:ps) | p*p > n = [n] | n `mod` p == 0 = p : factor (n `div` p) (p:ps) | otherwise = factor n ps problem_3 = last (primeFactors 600851475143) submitted by Chronic8888[link] [7 comments]

### CFP Bx'15: 4th International Workshop on BidirectionalTransformations

### garbage collection for a data structure

### Announcing the first class records library – Functional programming debugs you

### Book announcement: Robert Kowalski,LOGIC FOR PROBLEM SOLVING, REVISITED

### Announcing a solution to the records problem

### Announcing the first class records library – Functional programming debugs you

### Reading papers and other resources

My background is in computer engineering and I have been doing some stuff in haskell the last year and really liking it. I have also looked at Idris and other languages and coming from a background with imperative languages, it's really exciting.

Since I have mostly used books and google to learn and find help and information, I would like to find some other sources for more information, since my knowledge hub is quite sparse at the moment, about these things anyways.

New, experimental topics being studied right now about languages, techniques, functional programming, the future of it and so forth. Anything exciting, really. A place where these things are published, discussed and exposed, is what I am looking for. The format I had in mind is papers, but I will also read articles and books gladly.

Where are haskell/functional programming/new language research being published to? Where do you guys find these papers and articles? I would like to know about any resource where I can be exposed to great material.

Feel free to recommend me older papers on the topics also. I haven't read any about this yet, so most anything should be knew to me.

Go at it, thanks!

submitted by sirhcreffot[link] [16 comments]

### Philip Wadler: My email is a monster

My New Year's resolution is to look at my e-mail at most once a day. If you need a response in less than a day or two, please arrange it with me in advance or use a different medium. Cartoon courtesy of Oatmeal.

### This code produces an infinite output... why? it's abug in ghc?

### Tooling for equational reasoning in Haskell

### Haskell and Math, Math and Haskell...

I've heard it said over and over that Haskell is very mathematical, math-oriented, etc. I've been reading through this subreddit and reading lots of "should I learn haskell?" posts with a lot of people giving qualified yeses on the condition that the learner is interested in and good at math.

Well, I might be somewhat novel then: I've done a bit of programming in python, and I'm teaching myself C, but I'm curious about FP. Also, I'm not really terribly good at math. The last serious math class I passed was intermediate college algebra (the class you take before trigonometry).

Flash forward a few years, and I have a much different relationship to learning math: I'm curious about it, and I want to *understand* it more than just get correct answers. But I've still got a ways to go :)

Here's the question (aka, tl;dr): If knowing math can help you understand Haskell, does learning Haskell help you to better understand math? Will learning Haskell have benefits outside of, well, programming in Haskell?

submitted by tunabee[link] [17 comments]