[Haskell-cafe] take the keywords from a string

[Sara Kenedy]

Hi,

I tried to write function lexList by using an intermediate function
lisOfString as below:

module Lex where
lexList :: String -> [String]
lexList str = listOfString (lex str)
lexList [] =[]

listOfString :: [(String,String)] -> [String]
listOfString [(s1,s2)] = s1: listOfString (lex s2)
listOfString [("","")] = []


When I try function lisOfString as below, it runs forever (non-stop)
although I have the stop criteria for it ??

Lex> lisOfString ["test1","test2(test3)"]

Thanks in advance.

S.

> On 6/17/06, Neil Mitchell <ndmitchell at gmail.com> wrote:
> > Hi
> >
> > On 6/18/06, Sara Kenedy <sarakenedy at gmail.com> wrote:
> > > Sorry, I am not clear at some point in your answer:
> > >
> > > 1) The function
> > > lex :: String -> [(String,String)]
> > > and
> > > filter :: (a -> Bool) -> [a] -> [a]
> > > So, I did not see how filter can use the list of tuple string of lex.
> >
> > You can write a function lexList, of type String -> [String], by
> > repeatedly calling lex - its not too hard. Once you have this the
> > filter will work.
> >
> > Thanks
> >
> > Neil
> >
>