diff options
| -rw-r--r-- | src/GF/Text/Lexing.hs | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/src/GF/Text/Lexing.hs b/src/GF/Text/Lexing.hs index 8d4787de8..302a1db51 100644 --- a/src/GF/Text/Lexing.hs +++ b/src/GF/Text/Lexing.hs @@ -1,4 +1,4 @@ -module GF.Text.Lexing (stringOp) where +module GF.Text.Lexing (stringOp,opInEnv) where import GF.Text.Transliterations import GF.Text.UTF8 @@ -29,6 +29,22 @@ stringOp name = case name of "from_cp1251" -> Just decodeCP1251 _ -> transliterate name +opInEnv :: String -> String -> (String -> String) -> (String -> String) +opInEnv beg end op = concat . altern False . chop (lbeg, beg) [] where + chop mk@(lg, mark) s0 s = + let (tag,rest) = splitAt lg s in + if tag==mark then (reverse s0) : mark : chop (switch mk) [] rest + else case s of + c:cs -> chop mk (c:s0) cs + [] -> [reverse s0] + switch (lg,mark) = if mark==beg then (lend,end) else (lbeg,beg) + (lbeg,lend) = (length beg, length end) + altern m ts = case ts of + t:ws | not m && t==beg -> t : altern True ws + t:ws | m && t==end -> t : altern False ws + t:ws -> (if m then op t else t) : altern m ws + [] -> [] + appLexer :: (String -> [String]) -> String -> String appLexer f = unwords . filter (not . null) . f |