diff options
Diffstat (limited to 'src/PGF/CId.hs')
| -rw-r--r-- | src/PGF/CId.hs | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/src/PGF/CId.hs b/src/PGF/CId.hs index 0d1a2f5c6..fea304d9d 100644 --- a/src/PGF/CId.hs +++ b/src/PGF/CId.hs @@ -1,16 +1,19 @@ module PGF.CId (CId(..), - mkCId, readCId, prCId, - wildCId, - pCId, pIdent) where + mkCId, wildCId, + readCId, showCId, + + -- utils + pCId, pIdent, ppCId) where import Control.Monad import qualified Data.ByteString.Char8 as BS import Data.Char import qualified Text.ParserCombinators.ReadP as RP +import qualified Text.PrettyPrint as PP -- | An abstract data type that represents --- function identifier in PGF. +-- identifiers for functions and categories in PGF. newtype CId = CId BS.ByteString deriving (Eq,Ord) wildCId :: CId @@ -20,17 +23,18 @@ wildCId = CId (BS.singleton '_') mkCId :: String -> CId mkCId s = CId (BS.pack s) +-- | Reads an identifier from 'String'. The function returns 'Nothing' if the string is not valid identifier. readCId :: String -> Maybe CId readCId s = case [x | (x,cs) <- RP.readP_to_S pCId s, all isSpace cs] of [x] -> Just x _ -> Nothing -- | Renders the identifier as 'String' -prCId :: CId -> String -prCId (CId x) = BS.unpack x +showCId :: CId -> String +showCId (CId x) = BS.unpack x instance Show CId where - showsPrec _ = showString . prCId + showsPrec _ = showString . showCId instance Read CId where readsPrec _ = RP.readP_to_S pCId @@ -45,4 +49,7 @@ pIdent :: RP.ReadP String pIdent = liftM2 (:) (RP.satisfy isIdentFirst) (RP.munch isIdentRest) where isIdentFirst c = c == '_' || isLetter c - isIdentRest c = c == '_' || c == '\'' || isAlphaNum c
\ No newline at end of file + isIdentRest c = c == '_' || c == '\'' || isAlphaNum c + +ppCId :: CId -> PP.Doc +ppCId = PP.text . showCId |