X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Text%2FRead.hs;h=bcb2d0930ab395ab8f70bc0cfc99c723b5a906f9;hb=b0f8af46ab1a89f107f2d678d17b765cd97ff59f;hp=16a4d158eeb701b09d543019d768c866bbc4d0e5;hpb=eb05059d83b1c23cb5754b46f0ba5010ba80912d;p=haskell-directory.git

diff --git a/Text/Read.hs b/Text/Read.hs
index 16a4d15..bcb2d09 100644
--- a/Text/Read.hs
+++ b/Text/Read.hs
@@ -35,6 +35,7 @@ module Text.Read (
    module Text.ParserCombinators.ReadPrec,
    L.Lexeme(..),	
    lexP,		-- :: ReadPrec Lexeme
+   parens,		-- :: ReadPrec a -> ReadPrec a
 #endif
 #ifdef __GLASGOW_HASKELL__
    readListDefault,	-- :: Read a => ReadS [a]
@@ -56,4 +57,14 @@ import qualified Text.Read.Lex as L
 
 lexP :: ReadPrec L.Lexeme
 lexP = lift L.lex
+
+parens :: ReadPrec a -> ReadPrec a
+parens p = optional
+ where
+  optional  = p +++ mandatory
+  mandatory = do
+    L.Punc "(" <- lexP
+    x          <- reset optional
+    L.Punc ")" <- lexP
+    return x
 #endif