From f7d654cf658c8b0b04ec98e4c3bf216ae2976a26 Mon Sep 17 00:00:00 2001
From: Brent Yorgey <byorgey@cis.upenn.edu>
Date: Mon, 11 Feb 2013 22:00:44 -0500
Subject: [PATCH] implement a poor man's LANGUAGE pragma parser
---
.../Distribution/Client/Init/Heuristics.hs | 22 ++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/cabal-install/Distribution/Client/Init/Heuristics.hs b/cabal-install/Distribution/Client/Init/Heuristics.hs
index cc0e9f8ad9..1e2a4a14ab 100644
--- a/cabal-install/Distribution/Client/Init/Heuristics.hs
+++ b/cabal-install/Distribution/Client/Init/Heuristics.hs
@@ -124,9 +124,25 @@ findImportsAndExts projectRoot sf = do
-- Haskell parser since cabal's dependencies must be kept at a
-- minimum.
- exts = undefined --- XXX todo: parse LANGUAGE pragmas.
- . lines
- $ s
+ -- A poor man's LANGUAGE pragma parser.
+ exts = mapMaybe simpleParse
+ . concatMap getPragmas
+ . filter isLANGUAGEPragma
+ . map fst
+ . drop 1
+ . takeWhile (not . null . snd)
+ . iterate (takeBraces . snd)
+ $ ("",s)
+
+ takeBraces = break (== '}') . dropWhile (/= '{')
+
+ isLANGUAGEPragma = ("{-# LANGUAGE " `isPrefixOf`)
+
+ getPragmas = map trim . splitCommas . takeWhile (/= '#') . drop 13
+
+ splitCommas "" = []
+ splitCommas xs = x : splitCommas (drop 1 y)
+ where (x,y) = break (==',') xs
return sf { imports = modules
, extensions = exts
--
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