emacs haskell

Data ListLike an array in C, you can only save data of the same type.Two basic operations + + and:, + + for connecting two lists of course two list values must be of the same type: cons, used to construct the list, the first element must be a value, cannot be a list StringYou can see that the top and bottom results are identical, "denotes characters," "denotes strings, and C uses a pointer array to represent strings, and Haskell's string is a list of characters, so all operations of the

In Haskell, functions are generally performed using prefixes. But there is a way to change the prefix to infix.All we need to do is wrap the function together, and we can turn a function with 2 parameters into infix form.Prelude> "A" ' Notelem ' ["B"] true prelude> Notelem "a" ["B"] Truefunction infix, not only can have 2 parameters of the function into infix form, can also be more than 2 functions into infix form.But it looks pretty ugly.Prelude> FOL

I accidentally found this black hole question in the blog Park, which is suitable for Haskell practice. I tried to implement it with Haskell. Original question description: Sort the four numbers in a four-digit manner into a new number and a new number in a large to small arrangement. Then, the two numbers are subtracted and repeat this step, as long as the four digits in four digits are not repeated, t

In fact, this difference is just like the difference between a common function and a higher-order function. Isn't that easy to understand? Well, if you say you don't know what a high-order function is, don't read this article. Let's take a look at how I compared them. Let's take a look at how EQ is defined in Haskell. I call it "normal typeclasses" (to distinguish the functor typeclasses, I call it P ), here we define a typeclasses and define an acti

Prismsdata NewTask = SimpleTask String | HarderTask String Int | CompoundTask String [NewTask] deriving (Show)makePrisms ''NewTask*Main> a ^? _SimpleTaskJust "Clean"*Main> b ^? _HarderTaskJust ("Clean Kitchen",15)*Main> b ^? _HarderTask._2Just 15*Main> b _SimpleTask .~ "Clean Garage"HarderTask "Clean Kitchen" 15*Main> b _HarderTask._2 .~ 30HarderTask "Clean Kitchen" 30Manual calculation_Left = prism Left $ either Right (Left . Right)prism bt seta = dimap seta (either pure (fmap bt)) . righ

After emcas is started, the. emacs file is first loaded, which is in the home directory. For Linux, the home directory is your user directory. You can use "CD ~ "Command to enter this directory; for Windows, you need to configure the home directory in the environment variable options (my computer-> properties-> advanced-> environment variables ). Some people love Emacs and learn lisp for it, just to make

The key labeled in the command, the uppercase C for control, the keyboard is usually the CTRL key, and M for Meta, on the keyboard is usually the ALT key, S is the shift, on the keyboard is usually the SHIFT key, that is:C--->control M--->alt s-->shiftThese three keys in Emacs are usually used as the leading key combination, that is, you may need to hold down the key before executing a command, such as the Search command is c-s, to execute this comman

Today I wrote a Haskell code, and found that let sometimes need to add in, sometimes do not need to add in. The main reason for this is the Do code block. Do {let And the rest of the time you need to use in. What do I do if I want let to use in the Do code block? Dolet x = in Foo x Indentation is required because the indentation of Haskell is meaningful. OK, and then say a question about let indentation. F

Because I have proofread and edited it multiple times, I can see myArticleThere is no excitement when I appear in a magazine. In addition, the content of my work has also changed recently.ProgramMember. I am much more busy than before, so I have little time to focus on development. However, I can regard programs as a hobby and a tool for daily work. I can use what I like more purely. Now, I often write one or two lines of shell or Python scripts to treat my computer as my own robot and do some

YesodYesod is a WEB framework that uses the Haskell language.Installing YesodFirst update Haskell Platform to the latest version(Yesod relies on a lot of libraries, the version is inconsistent, it is easy to install failure)$ cabal install yesodInstalled yesod-1.4.5Hello World-- helloworld.hs{-# LANGUAGE OverloadedStrings #-}{-# LANGUAGE QuasiQuotes #-}{-# LANGUAGE TemplateHaskell #-}{-#

Environment used: Windows Server 2008 + GHC 7.6.3 (Haskell Platform 2013.2.0.0 Self-band) + Pandoc 1.12.4 Operation Steps: 1. Install Haskell Platform, download address: http://www.haskell.org/platform/. 2. Install pandoc, install command: Cabal install Pandoc 3. Run ghci on the command line 4. Refer to the corresponding module of Pandoc and run at the Prelude command prompt: : module Text.pandoc T

From: http://www.engr.uvic.ca /~ Dastone/emacs-keys.htmlEmacs keyboard shortcuts File Open CTRL-X, Ctrl-F Save CTRL-X, Ctrl-S Save CTRL-X, Ctrl-W Save all CTRL-X, S Revert to file CTRL-X, Ctrl-V Revert Buffer Meta-X, revert-Buffer Close Window/Buffer CTRL-X, K Quit CTRL-X, Ctrl-C Edit Undo CTRL

0 reply content: No! First, the list of Python is different from the list of Haskell .. The latter is a linked list, and the former is a dynamic array .. Then the implementation of Haskell's list comprehension relies on converting to map/filter (fusion optimization is not considered), and finally implementing it through recursion; the implementation of list comprehension in Python depends on the _ iter _ method (that is, the meaning of the itera