RULES for ByteString are not fired

[Thomas DuBuisson]

Another data point:

The bytestring 'break' rule fired fine for me (GHC 7.4.1 Linux x86-64).

On Mon, Aug 27, 2012 at 9:37 PM, Kazu Yamamoto <kazu at iij.ad.jp> wrote:
> Hello,
>
> I seems to us (my friends and me) that term rewriting rules for
> ByteString are not fired in recent GHCs.
>
>         6.12.3    OK
>         7.0.4     NG
>         7.4.1     NG
>         7.6.1RC1  NG
>
> For example, with the example from this ticket
>         http://hackage.haskell.org/trac/ghc/ticket/3703
> results in as follows:
>
> % ghc -O  -ddump-simpl-stats --make breakOn.hs
> 14 RuleFired
>   4 Class op showsPrec
>   2 Class op show
>   2 eqChar#->case
>   2 unpack
>   2 unpack-list
>   1 Class op ==
>   1 Class op >>
>
> There is no ByteString rules.
>
> Is this a bug or intention?
>
> --Kazu
>
> {-# LANGUAGE OverloadedStrings #-}
>
> import qualified Data.ByteString.Char8 as B
>
> main :: IO ()
> main = do
>     let string1 = B.pack "This is a string"
>         string2 = B.pack "This is another string"
>     print (breakOn ' ' string1)
>     print (breakOn ' ' string2)
>
> breakOn :: Char -> B.ByteString -> (B.ByteString, B.ByteString)
> breakOn c = B.break (c==)
>
>
>
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