Programming – Rahul Dongare

Haskell Programming Setup

— Create Program
mkdir haq
cd haq/
cat > Haq.hs
import System.Environment
main :: IO()
main = getArgs >>= print . haqify . head
haqify s = “Haq! ” ++ s

— add program to git
git init
git add Haq.hs
git commit -am “my first haskell git commit”
cabal init
git add haq.cabal Setup.hs LICENSE

— build and run it in sandbox
cabal sandbox init
cabal install -j
/Users/rahul/src/haq/.cabal-sandbox/bin/haq ME
sudo cp .cabal-sandbox/bin/haq /usr/local/bin/haq

— create API documentation
cabal configure
cabal haddock
cabal haddock –hyperlink-source –html-location=’http://hackage.haskell.org/package/haq/docs’ –contents-location=’http://hackage.haskell.org/package/haq’

w3m -dump dist/doc/html/haq/Main.html

— check code styling
cabal install hlint
hlint .

— add following to your cabal file (equivalent of build file)

test-suite tests
   ghc-options: -Wall
   default-extensions:  OverloadedStrings
   type: exitcode-stdio-1.0
   main-is: HSpecTests.hs
   build-depends:       base,
                        haq,
                        hspec

cabal install –enable-tests

cat > HSpecTests.hs
module Main where
 
import Haq
import Test.Hspec
 
main :: IO ()
main = hspec $ do
 
  describe "Validate haqify function" $ do
    it "haqify is supposed to prefix Haq! to things" $ do
      haqify "me" `shouldBe` "Haq! me"

cabal test

— Using Quick Test

cat > QuickTests.hs
 
import Data.Char
import Data.List
import Haq
import Test.QuickCheck
import Text.Printf
 
main  = mapM_ (\(s,a) -> printf "%-25s: " s >> a) tests
 
-- reversing twice a finite list, is the same as identity
prop_reversereverse s = (reverse . reverse) s == id s
    where _ = s :: [Int]
 
-- Dropping the "Haq! " string is the same as identity
prop_haq s = drop (length "Haq! ") (haqify s) == id s
    where haqify s = "Haq! " ++ s
 
tests  = [("reverse.reverse/id", quickCheck prop_reversereverse)
        ,("drop.haq/id",        quickCheck prop_haq)]

To run the test:
$ runhaskell Tests.hs

–Tab stable version of code
git tag 0.0

Reference :
https://www.haskell.org/haskellwiki/How_to_write_a_Haskell_program

Category: Programming

Haskell

Haskell-Cabal