why learn haskell

Bifoldableclass Bifoldable p where bifold :: Monoid m => p m m -> m bifold = bifoldMap id id bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> p a b -> m bifoldMap f g = bifoldr (mappend . f) (mappend . g) mempty bifoldr :: (a -> c -> c) -> (b ->

Applicative parsingUse the applicative type of Parser.Operators include use (), (), (), (), many, and so on.import Control.Monad-- showimport Text.Parsecimport Control.Applicative hiding (())number = many1 digitplus = char '+' *> numberminus = (:)

, and I also prefer the function, find a lap, Clojure seems to be able to, then I change Clojure, a week familiar with the language, and then switched over. The results found that clojure too dependent on Java, but also performance or not, to improve performance I have to give each variable manually type hint, then I need to use clojure, so it took one weeks to simply go to Haskell. Why switch so freely, is because I am all right when these languages

The basic types of JSON are--string, numbers, booleans, and NULL, which define the JSON type as follows--FILE:JSON.HSModule Json whereData Jvalue = jstring String | Jnumber Double | Jbool Bool | | Jobject

You can use the : T command to detect an expression type.　　A definite type must be capitalized in the first letter.First, Types　　Char　　Bool　　Int(bounded, high efficiency compared to integer type)　　Integer(unbounded, less efficient compared to type

24. Data. Set Set is between list and ing. All elements are unique. Fromlist constructs the set. Prelude data. Set> Let X = data. Set. fromlist [11,22, 33,44 Prelude data. Set> let y = data. Set. fromlist [91,32, 33,44, 55] Prelude data.

This error was encountered while compiling Libpandoc with cabal: Hshslua-0.3.12.o:unknown symbol ' ___s trtod ' ghc.exe:unable to load package ' hslua-0.3.12 ' Stuck in this place for a long time, and then found a workaround on the StackOverflow--

Installing Hdbc-sqlite3$ cabal install HDBC-Sqlite3Installed HDBC-sqlite3-2.3.3.1Prelude> :m Database.HDBC Database.HDBC.Sqlite3Prelude Database.HDBC Database.HDBC.Sqlite3>DB operationPrelude DATABASE.HDBC database.hdbc.sqlite3> Conn Run Conn

Talk about how beginners learn php ^_^ Author: silently The article at the beginning of the list of so many contact, it will inevitably make you feel a bit of ad's meaning, but can not be questioned, there is really so little performance to ^_^, although sometimes too meticulous will be said mother, but fortunately this meticulous for programming, or pretty good! From silently to others ask how to learn PHP

Table 6.1. Selected numeric types Type Description Double Double-precision floating point. A common choice for floating-point data. Float Single-precision floating point. Often

Reply content:You use node. js, what if you don't have to use NPM to pull a few hundred trillion things down? Python installation package looks just like more than 10 m. Just yesterday, only started with node, when installed, only 5m size, feel good

Below are some simple exercises in classCodeDouble X = x + xQuadruple x = double (Double X) Increment: int-> intIncrement n = (n + 1)Increment function. The parameter is an int-type variable and the return value is an int-type variable.

only elements of the same type can be stored in a list. 　　+ +: Merges two lists into a list. example, [1,2,3]++[4,5,6], the result is [1,2,3,4,5,6]. 　　: : Add the preceding element of ":" to the list after ":". The newly added element is in the

0. Reply content: If you use Node. js, can you use it if you don't need npm to pull dozens of hundreds of megabytes of data? The python installation package looks like a dozen mb. It was just yesterday that node was used. During the installation, it

Function, Monad, Arrowf :: Int -> (Int, Int)f = \x -> let y = 2 * x z1 = y + 3 z2 = y - 5 in (z1, z2)-- ghci> f 10-- (23, 15)fM :: Int -> Identity (Int, Int)fM = \x -> do y runIdentity (fM 10)-- (23,15)fA :: Int -> (Int, Int)fA =

1. An error occurred while running the command cabal install glib: Cannot find GTK2HSC2HS Please install ' gtk2hs-buildtools ' and check this install directory is in your PATH (e.g. home/.cabal/bin). 2. Run Command cabal install Gtk2hs-buildtools

Learn how to use Mantle in 3 minutes !, Learn mantle in 3 minutes Recently, it was my turn to explain Mantle at the iOS technology sharing meeting of the company's mobile internet business department. So I went to the Internet to search for materials. Finally, based on the articles in the next three links, I read them in order and summarized them, it took three minutes to share with you what this Mantle was

technology trend of * production systems, so as to remain unchanged. "Inside Ole 2" *** tips **: 1) Delphi/BCB/vB can quickly build interfaces, but it is not a good platform to really learn and understand the system, however, if you have time to read the source code of VCL, you can also learn a lot from how Borland encapsulates the system. 2) Learning ASM has great benefits for understanding C ++. Soft-ice

. PracticeIn the course of learning, reading books is not enough, and practice is the most important. The so-called learning and application, such as exercises/learning some small scripts/in the course of "Python core programming 2, here are several sites for learning Python script instances: (1). Code sharing list-Python (2). python code library Https://searchcode.com/ (4). the best choice for github is to search more related projects, check people's code, and copy the wheel !! 4. Advanced

Php Chinese network (www.php.cn) provides the most comprehensive basic tutorial on programming technology, introducing HTML, CSS, Javascript, Python, Java, Ruby, C, PHP, basic knowledge of MySQL and other programming languages. At the same time, this site also provides a large number of online instances, through which you can better learn programming... Reply: Which programming language is the most difficult? Not C ++, not Lisp, Your first language. W