On Mon, 2009-03-02 at 01:53 -0800, Thomas DuBuisson wrote:
All,
http://hackage.haskell.org/trac/ghc/ticket/3058
Attached is a patch for Text.PrettyPrint.HughesPJ that adds a 'hex' function to print hexidecimal numbers.
The only point that I exepect to be contended is it varies slightly from the surrounding functions in that it allows one to control the number of characters printed:
There are a number of other functions from the Numeric module we should also consider. These are all the ones that return ShowS, the equivalent of the Doc type. showEFloat :: (RealFloat a) => Maybe Int -> a -> ShowS showFFloat :: (RealFloat a) => Maybe Int -> a -> ShowS showGFloat :: (RealFloat a) => Maybe Int -> a -> ShowS showHex :: (Integral a) => a -> ShowS showInt :: (Integral a) => a -> ShowS showIntAtBase :: (Integral a) => a -> (Int -> Char) -> a -> ShowS showOct :: (Integral a) => a -> ShowS showFloat :: (RealFloat a) => a -> ShowS showSigned :: (Real a) => (a -> ShowS) -> Int -> a -> ShowS
While we can argue about the consistancy issues, I almost always want to control the number of digits when dealing with hex. Hence I feel this is a reasonable special case.
For some reason I thought I remembered that the Numeric show functions also allowed fixed width 0-padded display but it appears they do not, except by manually rendering and adding leading 0's. Note the show float functions take an optional precision. Perhaps that's a sensible approach for optional fixed width octal and hexadecimal display.
Secondary Issues: 1) Is there a repo for pretty? I didn't see one on code.haskell.org
It's on darcs.haskell.org along with ghc and the other core libs.
2) If I submit a ticket+patch to move Text.PrettyPrint.HughesPJClass (from prettyclass, Augustsson) into Text.PrettyPrint (of the 'pretty' package) would anyone object? It feels mis-placed / I feel things need consolidated.
That's a much bigger change. I suggest a separate ticket and discussion for that. There's a rather large design space and range of use cases. Duncan