Haskell Regex.POSIX is not supported 'word boundary'
use package: Text.RE.TDFA.String instead

-- /Users/cat/myfile/bitbucket/haskell/regexExample.hs 

--{-# LANGUAGE QuasiQuotes                      #-}
--import Text.RE.TDFA.String
main = do 
    -- replace word boundary, replace one, and replace all
    let s1 = "mydog dog dog (dog)" ?=~/ [ed|${adr}(\):?///< div class="dog">${adr}< /div> |]
    let s2 = "mydog dog dog (dog)" *=~/ [ed|${adr}(\):?///< div class="dog">${adr}< /div> |]
    putStrLn $ "replace one: =>[" ++ s1 ++ "]"
    putStrLn $ "replace all: =>[" ++ s2 ++ "]"

re1 = "my food"         =~ "foo"::Bool                      -- True
re2 = "my food foo"     =~ "foo"::String                    -- "foo"
re3 = "my foolish fool" =~ "foo."::[[String]]               -- [["fool"],["fool"]]
re4 = "my foolish fool" =~ "foo."::(String, String, String) -- ("my ","fool","ish fool")

-- word boundary, search word and replace
let s = "mydog dog-- dog pig cat dog fox"
searchReplace s word "[\\0]"

let r1 = mkRegex "google"
let input = "http://google.com"
let replace1 = "[\\0]"
putStrLn $ subRegex r1 input replace1            -- http://[google].com

let r3 = mkRegex "(na)+"
putStrLn $ subRegex r3 "banana" "[\\0] {\\1}"

let r5 = mkRegex ".*\\.pdf"
putStrLn $ subRegex r5 "http://file.pdf" "[\\0]" -- [http://file.PDF]

-- capture group, capture email address
let r6 = mkRegex "([A-Za-z._-]+)+@(([a-z])+\\.([a-z]{2,4}))"
putStrLn $ subRegex r6 "root_admin.last-name@gmail.com"   "7. [\\0] {\\1}{\\2}"

let r7 = mkRegexWithOpts "(.*\\.pdf)" True False
let input = "/home/user/file/mybook.PDF"
let callMeMaybe = matchRegex r7 input

let r7 = mkRegexWithOpts "(\\.pdf)" True False
let input = "/home/user/file/mybook.PDF"
let callMeMaybe = matchRegex r7 input

-- capture phone number
let p1 = mkRegex "[0-9]{3}[ -]?[0-9]{3}[ -]?[0-9]{4}" 
-- replace string
putStrLn $ subRegex p1 "779-123-4483"  "[\\0]"    -- [416-123-4483]

-- split Regex
print $ splitRegex(mkRegex ":") "PaloAlto:MountainView" -- ["PaloAlto","MountainView"]

-- capture function in ObjectiveC
let me = mkRegex "(-|\\+)[[:space:]]*\\([[:space:]]*[[:print:]]+[[:space:]]*\\)[[:space:]]*[[:graph:]]+\
\[[:space:]]*:?[[:space:]]*([[:space:]]*[[:graph:]]+[[:space:]]*:[[:space:]]*[[:graph:]]+[[:space:]]*)*"

putStrLn $ subRegex me "- (NSstring*) swap :" "[\\0]" -- [- (NSstring*) swap :]

putStrLn $ subRegex me "- (NSstring*) method:(Integer)num width:(Integer)width\ 
\ height:(NSString*)str" "12. [\\0]"
-- [- (NSstring*) method:(Integer)num width:(Integer)width  height:(NSString*)str]

let r7 = mkRegex "([A-Za-z]+)" 
let count = matchCount r7 "haskell java C++ ObejctiveC aa#" 
putStrLn $ "count = " ++ show count

let r8 = mkRegex "[a-z]+"
let bo = matchTest r8 "22323"
putStrLn $ "Is matched = " ++ show bo -- return True