- Haskell-Cafe - Haskell.org

Update of haskell cafe on google groups
by Graham Berks 28 Apr '12

28 Apr '12

Has this stopped working ? Seems a bit out of date ? Thanks

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Re: [Haskell-cafe] [Haskell] ANNOUNCE: planar-graph-1.0
by Ivan Lazar Miljenovic 27 Apr '12

27 Apr '12

On 28 April 2012 11:34, Christian Höner zu Siederdissen <choener(a)tbi.univie.ac.at> wrote: > Hi, > > one minor correction: >> This probably won't be of many use to people > for bioinformatics I'd disagree ;-) I'll take a look at your library. > > (for example, RNA /secondary/ structure forms a planar graph) I stand corrected! -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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ANNOUNCE: planar-graph-1.0
by Ivan Lazar Miljenovic 27 Apr '12

27 Apr '12

I uploaded this [1] yesterday, posted the blog article [2] about it... but forgot to send a message to the lists! [1]: http://hackage.haskell.org/package/planar-graph [2]: http://ivanmiljenovic.wordpress.com/2012/04/27/announcing-planar-graph/ planar-graph is an implementation of, strangely enough, planar graphs (that is, a graph that contains an embedding on a surface, can be drawn with no edge crossings and has a specific ordering of edges). It handles graphs on planes and spheres, but I'm not sure about other surfaces (and there seems to be little demand for such). This probably won't be of many use to people, but as I described in the blog post, I've been using this as a test bed for graph library design (specifically usage of abstract node/edge identifiers, using half-edges and the serialisation/encoding setup). -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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Re: [Haskell-cafe] [Haskell] ANN: Portackage - a hackage portal
by Andrew Seniuk 27 Apr '12

27 Apr '12

Hi Derek, Thanks for your comments. Yes, I am probably going to focus on making it work as a web service and stay away from platform-specific mobile apps. Not been thinking mobile much at all, since the quantities of data are taxing even to my laptop, and also I'm inclined to believe people are mostly at a laptop or desktop when coding Haskell. However, I'm planning to try server-side sorting and filtering, and compare performance. No DB is used on the server yet, but it would be simple enough I suppose -- all this is quite new territory for me. Also my shared hosting resource limits may become a problem if this gets a lot of use. On the other hand, was planning to use persistence (cookies i guess?) to save the data on the client, so that patches based on Hackage RSS could be applied incrementally. Also, I think the sorting could be faster by sending per-column lists of indices. But maybe it is just the browser rendering which is taking all the time? I'll take this opportunity to announce a few improvements: - shift-click a row to see the Hackage page (bare click does nothing) - per-column filtering widgets Presently working on getting the "last updated" column, this information is not in a .cabal file but I'm hoping it is in the TAR metadata... The link again: http://www.fremissant.net/portackage A.

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Uploading a new hsc2hs
by Thomas DuBuisson 27 Apr '12

27 Apr '12

Warning: I, not the maintainer of hsc2hs, will be uploading a trivial fix for hsc2hs to hackage (new build deps). Even after public attempts to contact anyone in charge of hsc2hs (last January) there still has been no word. Speak now or forever hold your peace. Cheers, Thomas P.S. I still think c2hs is the right philosophy even if it's too verbose.

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Annotations in abstract syntax tree
by j.romildo＠gmail.com 27 Apr '12

27 Apr '12

Hello. I need to annotate abstract syntax tree with additional information in a compiler. Using the Annotations package[1] I have written the following small program: import Annotations.F.Annotated import Annotations.F.Fixpoints data ExprF r = Num Double | Var String | Add r r | Sub r r | Mul r r | Div r r deriving (Eq,Show) type BareExpr = Fix ExprF e :: BareExpr e = In (Mul (In (Num 5)) (In (Add (In (Var "x")) (In (Num 8))))) type ValExpr = Fix (Ann Double ExprF) type Memory = [(String,Double)] eval :: Memory -> BareExpr -> ValExpr eval _ (In (Num x)) = In (Ann x (Num x)) eval m (In (Var x)) = let y = case lookup x m of Just k -> k Nothing -> 0 in In (Ann y (Var x)) eval m (In (Add x y)) = op m (+) Add x y eval m (In (Sub x y)) = op m (-) Sub x y eval m (In (Mul x y)) = op m (*) Mul x y eval m (In (Div x y)) = op m (/) Div x y op m f k x y = let x'@(In (Ann v1 _)) = eval m x y'@(In (Ann v2 _)) = eval m y in In (Ann (f v1 v2) (k x' y')) With these definitions we can represent simple arithmetic expressions and we can also evaluate them, annotating each node in the abstract syntax tree with its corresponding value. Now I want to add statements to this toy language. One statement may be a print statement containing an expression whose value is to be printed, an assign statement containing an identifier and an expression, or a compound statement containing two statements to be executed in sequence. How the data types for statements can be defined? How a function to execute an statement anotating its node with the corresponding state (memory plus output) after its execution can be defined? Without annotations the type of statements could be: data Stm = PrintStm Expr | AssignStm String Expr | CompoundStm Stm Stm How to enable annotations in this case? Note that Stm uses both Expr and Stm. [1] http://hackage.haskell.org/package/Annotations Romildo

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Automatic discovery of tests
by G 27 Apr '12

27 Apr '12

Hi, trying to learn haskell and the associated build env. I come from a java/scala world so trying to understand the how to invoke tests. Have a cabal file that invokes a main function to execute a test. But wondering if there is any automatic discovery of tests as per junit. I have seen test-framework-th but to me that implies putting a testGroupGenerator into each module. Am i correct about that and if so is there an example of calling multiple modules tests ? Or is there a better way just to invoke specific functions prefixed with case_ prop_ etc in the entire src/test directory of the cabal build ? Thanks

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Re: [Haskell-cafe] [Haskell] ANN: Portackage - a hackage portal
by Andrew Seniuk 27 Apr '12

27 Apr '12

Excuse the delay, I have no home internet. > On Fri, Apr 27, 2012 at 1:16 AM, <briand(a)aracnet.com> wrote: > Great idea. Maybe the format can start as compactly as possible, > i.e. 1 entry per line to make it easy to browse as many entries > as possible in one page. > > It looks as though disabling just the dependencies would go a > long way to accomplish that. Yep, and in fact the version I uploaded while reading your message has the deps column elided (and one or two others). Enforcing single-line rows is a but a few tweaks away. The thing is, the module namespace was the main motivator for this project, so I'm also seeing whether I can get away with a single view, package-oriented as presently, and still give good focus to the modules names. Soon I hope to include "accordion" views of the module namespace, with cookie-based (?) persistent state so user's collapse/expand tree state is preserved. > I'd like to vote to make the synopsis to be the second column. > > will each column type have an enable/disable ? I like the idea (although that one wasn't in the upload). Hopefully when I explore the JavaScript UI tools a bit more, the columns (key structure) will be totally configurable by drag-and-drop, with columns sizable, and keys selected from a listbox. (?) stuff like that > it's probably best if a click on a specific target, say the actual > name of the package, sends you to the hackage entry instead of a > click anywhere on the row. I find myself clicking on the page > by accident and it sending me off to some random hackage entry. :) That's a feature! But seriously, you're right, and as a bonus the links can be specific to the columns (package -> hackage, modules -> API pages, homepages -> hps, maintainer -> sendto [1]). (A 2-finger or Mod- click anywhere on a row might still be nice, but a bare tap is admittedly way too accident prone with touch input.) > I really like the idea - makes your hackage surfing > much more enjoyable ! > > Brian And thank-you for sharing your thoughts! I'm committed to improving it, until the ideas run out. > On Fri, Apr 27, 2012 at 4:12 AM, Christoph Breitkopf <chbreitkopf(a)googlemail.com> wrote: > this already looks great. So here's my wish-list, in case you have > too much time on yours hands ;-) Thanks! Yes I suppose I do have too much time on my hands, but the pain of that is conterbalanced by all the excitement. > Quality/popularity indicators (I'm aware that some of these are > real work and better provided by hackage itself): > - used by how many other packages (number of edges to that package > in the dependency graph of all packages) > - haddock coverage, test coverage, etc. > - like, +1, whatnot button > - link to issue tracker, if there is one If there's interest, this could become integrated with hackage at some point in the future. Next thing is to get a "last upload" field which can replace the version field. The codependency graph :) would be a nice metric to add, I'll look into it. I remember seeing a package that does this someplace on hackage. The +1 button is a good one! In short I'll try to implement all these ideas, thanks to you both for the encouraging comments. -Andrew [1] I omitted the maintainer column, thinking its inclusion might be harmful, making the emails so easy for a bot to collect.

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ANN: Portackage - a hackage portal
by Andrew Seniuk 26 Apr '12

26 Apr '12

Hello, This is to announce a provisional webpage to summarise hackage.haskell.org. http://www.fremissant.net/portackage It is a lot of data, so will be a bit slow to load. Columns can be sorted by clicking the headers, but this will also take some seconds on a typical client. The initial sort is by module name. Clicking a table row links to the project page on hackage. Although I believe this is a complete list of all packages/modules in hackage, it is probably still buggy, so if you see anything amiss please let me know. Also, a subsequent version in the near future will update automatically based on the http://hackage.haskell.org/packages/archive/recent.rss RSS feed, but for now it's based on a recent snapshot. Haskell code which prepares the page will be released after a few more days testing and refinement. Some previous work [1] provided a list of all modules, but is not being maintained, and I was unable to rearouse the author's interest. Feature requests and suggestions are welcome! Kind Reg'ds, Andrew Seniuk [1] http://folk.ntnu.no/hammar/explore-hackage/

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Re: [Haskell-cafe] [Haskell] ANN: Portackage - a hackage portal
by Andrew Seniuk 26 Apr '12

26 Apr '12

Jonathan, On Thu, Apr 26, 2012 at 4:13 PM, Jonathan Daugherty <jtd(a)galois.com> wrote: >> Although I believe this is a complete list of all packages/modules in >> hackage, it is probably still buggy, so if you see anything amiss >> please let me know. > > It might not be showing the most recent releases of everything. As an > example, it shows a much older version of my vty-ui library (1.0) and > its metadata, instead of the latest version, 1.5. As a result the > version, module list, description, homepage, etc., are not current. Thank-you, I'd realised this issue but forgot to address it. It is due to a false assumption on my part that the .cabal entries in the 00-index.tar file were in increasing version order. I'll address this problem today. Cheers, Andrew

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