Hello, Does this help?
http://www.serpentine.com/blog/2007/02/27/a-haskell-regular-expression-tutorial/ j. At Tue, 23 Dec 2008 11:21:41 -0800, Lyle Kopnicky wrote: > > [1 <multipart/alternative (7bit)>] > [1.1 <text/plain; ISO-8859-1 (7bit)>] > I'm trying to migrate code from using the old Text.Regex to the new > Text.Regex.Base. But, I'm getting type errors. I can't even create a regex. > Looking at the docs, it seems like this should print "bcd": > > import Data.Array > import Text.Regex.Base > import Text.Regex.Posix > > rx = makeRegex "a(.*)A" > > Just (_, mt, _) = matchOnceText rx "abcdA" > > main = putStrLn (fst (mt ! 0)) > > > But I get an error: > > src\regex.hs:5:5: > No instance for (RegexMaker regex compOpt execOpt [Char]) > arising from a use of `makeRegex' at src\regex.hs:5:5-22 > Possible fix: > add an instance declaration for > (RegexMaker regex compOpt execOpt [Char]) > In the expression: makeRegex "a(.*)A" > In the definition of `rx': rx = makeRegex "a(.*)A" > > src\regex.hs:7:18: > No instance for (RegexLike regex [Char]) > arising from a use of `matchOnceText' at src\regex.hs:7:18-41 > Possible fix: > add an instance declaration for (RegexLike regex [Char]) > In the expression: matchOnceText rx "abcdA" > In a pattern binding: Just (_, mt, _) = matchOnceText rx "abcdA" > > Why does it say there is no instance? Isn't the instance imported by > Text.Regex.Posix? > > Why in the world is it so complicated just to get a matched substring out of > the text? Is there an easier way? > > Thanks, > Lyle > [1.2 <text/html; ISO-8859-1 (7bit)>] > > [2 <text/plain; us-ascii (7bit)>] > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
