haskell parsec

Take advantage of the opportunity to reinstall your Linux virtual machine by documenting the process of installing Haskell, and helping readers who are still hesitant to wander outside the Haskell Gate.Basic concepts:Haskell:is a universal functional language, almost able to do whatever kind of development, including command line, GUI, database, Web. Source code can cross platform: Linux,mac, Windows, FreeB

Source Address: Haskell Learning-functorWhat is functor functor is an object that can perform map operations, and functor is like an expression with a semantic appended to it, which can be likened to a box. The definition of functor can be interpreted like this: given a mapping of A to B function and a box, the result will return to the box loaded with B. Fmap can be thought of as a function that accepts functions and a functor , which apply function

: center; } textarea { overflow-x: auto; } .linenr { font-size:smaller } .code-highlighted {background-color:#ffff00;} .org-info-js_info-navigation { border-style:none; } #org-info-js_console-label { font-size:10px; font-weight:bold; white-space:nowrap; } .org-info-js_search-highlight {background-color:#ffff00; color:#000000; font-weight:bold; } /*]]>*/--> Write the custom installation configuration table of contents for the ha

Example of a failed Haskell FFI binding /*--> html { font-family: Times, serif; font-size: 12pt; } .title { text-align: center; } .todo { color: red; } .done { color: green; } .tag { background-color: #add8e6; font-weight:normal } .target { } .timestamp { color: #bebebe; } .timestamp-kwd { color: #5f9ea0; } .right {margin-left:auto; margin-right:0px; text-align:right;} .left {margin-left:0px; margin-right:auto; text-align:le

I know, a lot (are there actually many ?) People will think that pure static strong functional language such as Haskell is too serious and abstract. It is only suitable for cold and hard scientific tasks. However, dear Paul Hudak (http://cs-www.cs.yale.edu/homes/hudak/), let us see in a speech named "Haskell and the arts, haskell, the original rigorous thinking,

Manual calculation of Set mapped 5 [[+]set l b = runIdentity . l (\_ -> Identity b)mapped = sets fmapsets f g = taintedDot (f (untaintedDot g))instance Settable Identity where untainted = runIdentity untaintedDot = (runIdentity #.) taintedDot = (Identity #.)set mapped 5 [1,2,3]= runIdentity . (sets fmap) (\_ -> Identity 5) $ [1,2,3]= runIdentity $ sets fmap (\_ -> Identity 5) $ [1,2,3]= runIdentity $ taintedDot (fmap (untaintedDot (\_ -> Identity 5))) $ [1,2,3]= runIdentity $ (Identity .) (fm

Preview, reviewPrelude Control.Lens> view _Left (Left "abc")"abc"Prelude Control.Lens> view _Right (Right "abc")"abc"Prelude Control.Lens> view _Just (Just "abc")"abc"Prelude Control.Lens> preview _Left (Left "abc")Just "abc"Prelude Control.Lens> review _Left "abc"Left "abc" The preview and review functions handle either such and typesThe preview function walks up a branch.The review function goes down one branch. Preview, review version of the operatorPrelude Control.Lens> Left "a

Distributiveclass Functor g => Distributive g where distribute :: Functor f => f (g a) -> g (f a) distribute = collect id collect :: Functor f => (a -> g b) -> f a -> g (f b) collect f = distribute . fmap f distributeM :: Monad m => m (g a) -> g (m a) distributeM = fmap unwrapMonad . distribute . WrapMonad collectM :: Monad m => (a -> g b) -> m a -> g (m b) collectM f = distributeM . liftM fcotraverse :: (Distributive g, Functor f) => (f a -> b) -> f (g a) -> g bcotraverse f

Frege is a purely functional programming language inspired by the Haskell language. The Frege program will be compiled into Java and run on the JVM. It is so similar to Haskell that some people call it Haskell on the JVM. The name of Frege is to commemorate the German mathematician, logic, philosopher Gottlob Frege.The main features of language Pure Func

Frege is a purely functional programming language inspired by the Haskell language. The Frege program will be compiled into Java and executed on the JVM. It is so similar to Haskell. So that it was called Haskell on the JVM. The name of Frege is to commemorate the German mathematician, logic, philosopher Gottlob Frege.The main features of language Pure F

first few elements maximum returns the list maximum, Minmum returns the minimum sum sum elem determines whether the element is in the list, Use infix expression 4 \elem ' [1,2,3,4] ' range operation using: To generate a large number of contiguous data, such as [1..100] can use the first two elements to represent the step, such as [1,3...100] generate 100 in the odd Haskell support an infinite list, such as [1,2..],