Pragmas in Lexer

JP Moresmau jpmoresmau at
Sat Dec 29 11:24:23 CET 2012

Hello, I'm using the GHC lexer to parse some haskell code containing a
language pragma, in GHC 7.4.2

module Main where

import GHC
import GHC.Paths ( libdir )
import Lexer
import qualified MonadUtils as GMU
import StringBuffer
import FastString (mkFastString)
import SrcLoc
import ErrUtils (mkPlainErrMsg)

main = do
        let contents="{-# LANGUAGE CPP #-}\nmodule Main
        runGhc (Just libdir) $ do
                flg <- getSessionDynFlags
                let sb=stringToStringBuffer contents
                let lexLoc = mkRealSrcLoc  (mkFastString "<interactive>") 1
                let prTS = lexTokenStream sb lexLoc flg
                case prTS of
                        POk _ toks    -> GMU.liftIO $ print $ map (show .
unLoc) toks
                        PFailed l msg -> GMU.liftIO $ print $ mkPlainErrMsg
l msg

This prints:
["ITblockComment \" CPP #\"","ITmodule","ITconid
\"Main\"","ITwhere","ITvocurly","ITvarid \"main\"","ITequal","ITvarid

Why is the first token ITblockComment and not ITlanguage_prag? Do I need to
enable something special to get pragma tokens?


JP Moresmau
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Glasgow-haskell-users mailing list