Closed
Description
When trying to use c2hs 0.17.2 together with language-c 0.4.5 I get an error "Prelude.read: no parse".
This boils down to a change in representation of Ident in language-c, seems like, so the Read instance for Ident in src/C2HS/Gen/Monad.hs fails to work. The new Ident looks like the following
Ident "GIBaseInfo" 436424608 (NodeInfo ("/usr/include/gobject-introspection-1.0/gitypes.h": line 145) (("/usr/include/gobject-introspection-1.0/gitypes.h": line 145),10) (Name {nameId = 56188}))
The following Read instance fixes the issue for me:
-- Remove everything until the next element in the list (given by a
-- ","), the end of the list (marked by "]"), or the end of a record
-- "}". Everything inside parenthesis is ignored.
chopIdent :: String -> String
chopIdent str = goChop 0 str
where goChop :: Int -> String -> String
goChop 0 rest@('}':_) = rest
goChop 0 rest@(',':_) = rest
goChop 0 rest@(']':_) = rest
goChop level ('(':rest) = goChop (level+1) rest
goChop level (')':rest) = goChop (level-1) rest
goChop level (_ :rest) = goChop level rest
goChop level [] = []
extractIdent :: String -> (Ident, String)
extractIdent str =
let isQuote c = c == '\'' || c == '"'
(ideChars, rest) = span (not . isQuote)
. tail
. dropWhile (not . isQuote) $ str
in
if null ideChars
then error $ "Could not interpret " ++ show str ++ "as an Ident."
else (internalIdent ideChars, (chopIdent . tail) rest)
-- super kludgy (depends on Show instance of Ident)
instance Read Ident where
readsPrec _ str = [extractIdent str]