commands for displaying transliteration tables

src-3.0/GF/Text/Lexing.hs

@@ -1,5 +1,6 @@
 module GF.Text.Lexing (stringOp) where
 
+import GF.Text.Transliterations
 import GF.Text.UTF8
 
 import Data.Char
@@ -19,7 +20,7 @@ stringOp name = case name of
   "unwords"    -> Just $ appUnlexer unwords
   "to_utf8"    -> Just encodeUTF8
   "from_utf8"  -> Just decodeUTF8
-  _ -> Nothing
+  _ -> transliterate name
 
 appLexer :: (String -> [String]) -> String -> String
 appLexer f = unwords . filter (not . null) . f

src-3.0/GF/Text/Transliterations.hs

@@ -0,0 +1,87 @@
+module GF.Text.Transliterations (transliterate,transliteration,characterTable) where
+
+import GF.Text.UTF8
+
+import Data.Char
+import qualified Data.Map as Map
+
+transliterate :: String -> Maybe (String -> String)
+transliterate s = case s of
+  'f':'r':'o':'m':'_':t -> fmap appTransFromUnicode $ transliteration t
+  't':'o':'_':t -> fmap appTransToUnicode $ transliteration t
+  _ -> Nothing
+
+transliteration :: String -> Maybe Transliteration
+transliteration s = case s of
+  "devanagari" -> Just transDevanagari
+  "thai" -> Just transThai
+  _ -> Nothing
+
+characterTable :: Transliteration -> String
+characterTable = unlines . map prOne . Map.assocs . trans_from_unicode where
+  prOne (i,s) = unwords ["|", show i, "|", encodeUTF8 [toEnum i], "|", s, "|"]
+
+data Transliteration = Trans {
+  trans_to_unicode   :: Map.Map String Int,
+  trans_from_unicode :: Map.Map Int String
+  }
+
+appTransToUnicode :: Transliteration -> String -> String
+appTransToUnicode trans = 
+  concat .
+  map (\c -> maybe c (return . toEnum) $
+             Map.lookup c (trans_to_unicode trans)
+      ) . 
+  unchar
+
+appTransFromUnicode :: Transliteration -> String -> String
+appTransFromUnicode trans = 
+  concat .
+  map (maybe "?" id . 
+       flip Map.lookup (trans_from_unicode trans)
+      ) . 
+  map fromEnum
+
+
+-- conventions: 
+--   each character is either [letter] or [letter+nonletter]
+--   when using a sparse range of unicodes, mark missing codes as "-" in transliterations
+
+mkTransliteration :: [String] -> [Int] -> Transliteration
+mkTransliteration ts us = Trans (Map.fromList (tzip ts us)) (Map.fromList (uzip us ts)) 
+  where
+    tzip ts us = [(t,u) | (t,u) <- zip ts us, t /= "-"]
+    uzip us ts = [(u,t) | (u,t) <- zip us ts, t /= "-"]
+
+
+unchar :: String -> [String]
+unchar s = case s of
+  c:d:cs 
+   | isAlpha d -> [c]   : unchar (d:cs)
+   | isSpace d -> [c]   : unchar cs
+   | otherwise -> [c,d] : unchar cs
+  [_]          -> [s]
+  _            -> []
+
+transThai :: Transliteration
+transThai = mkTransliteration allTrans allCodes where
+  allTrans = words $
+    "-  k  k1 -  k2 -  k3 g  c  c1 c2 s' c3 y' d' t' " ++
+    "t1 t2 t3 n' d  t  t4 t5 t6 n  b  p  p1 f  p2 f' " ++
+    "p3 m  y  r  -  l  -  w  s- s. s  h  l' O  h' -  " ++
+    "a. a  a: a+ i  i: v  v: u  u: -  -  -  -  -  -  " ++
+    "e  e' o: a% a& L  R  S  T1 T2 T3 T4 K  -  -  -  " ++
+    "N0 N1 N2 N3 N4 N5 N6 N7 N8 N9 -  -  -  -  -  -  "
+  allCodes = [0x0e00 .. 0x0e7f]
+
+transDevanagari :: Transliteration
+transDevanagari = mkTransliteration allTrans allCodes where
+  allTrans = words $
+    "~  *  -  - " ++
+    "a- A- i- I- u- U- R- -  -  -  e- E- -  -  o- O- " ++
+    "k  K  g  G  N: c  C  j  J  n: t. T. d. D. n. t  " ++
+    "T  d  D  n  -  p  P  b  B  m  y  r  -  l  -  -  v  " ++
+    "S  s. s  h  -  -  r. -  A  i  I  u  U  R  -  -  " ++
+    "-  e  E  o  O "
+  allCodes = [0x0901 .. 0x094c]
+