cabal exec -- ghc --make scanner.hs ./scanner input.json output.html

Origin Json File

{ "quiz": { "sport": { "q1": { "question": "Which one is correct team name in NBA?", "options": [ "New York Bulls", "Los Angeles Kings", ... ], "answer": "Huston Rocket", "age": 31, "case": true } }, ... } }

HTML opened in browser

• About $ and .

• Maybe and Just

• IO _ when return type is IO _, use <- to assign it to a variable

  addOne :: Int -> IO Int addOne x = do return x main = do value <- addOne 1 print(value)

• unusual show

  > show '"' "'\"'" :: String > show '\\' "\\\\" :: String > show 'x' "'x'" :: String

  if want to convert Char to String

  > ['x'] "x" :: [Char]

regex cheat sheet Install

$ cabal install regex-pcre

Error may occur

Wrap.hsc:148:10: fatal error: 'pcre.h' file not found #include <pcre.h>

solution for mac

brew install pcre cabal install regex-pcre 

Manage packages in local directroy

cabal sandbox init

to use ghci with packages with local sandboxs

# For GHC < 7.6 $ ghci -no-user-package-conf -package-conf .cabal-sandbox/x86_64-osx-ghc-8.2.2-packages.conf.d

to comile hs file with local sandboxs

cabal exec -- ghc --make myhaskell.hs