Hi, First of all In ghci
guessKeys "modF1" "*** Exception: Test.hs:8:10-85: Irrefutable pattern failed for pattern (_, _, _ , [key])
Because, the pattern "xK_(\\w+)" does not match with your input "modF1", as you already tried in the bbb function. *Main> bbb "modF1" ("modF1","","",[]) Note that the 4th component is an empty list, which does not match with your specify in 2nd where clause (_, _, _, [key]) = line =~ "xK_(\\w+)" :: (String, String, String, [String])
aaa "modF1" <interactive>:1:0: No instance for (Text.Regex.Base.RegexLike.RegexContext Regex [Char] [[a]]) arising from a use of `aaa' at <interactive>:1:0-10
You need to give a type annotation to the function aaa so that the type class instance can be "resolved".
Regards, Kenny