duncan.coutts:
On Wed, 2006-07-05 at 05:58 -0500, John Goerzen wrote:
Hi,
In MissingH, I have a bunch of little functions that operate on lists. Some, like uniq (which eliminates duplicate elements in a list), operate on (Eq a => [a]) lists. Others, like strip (which eliminates whitespace at the start and end), operate on Strings only.
Most functions of both types would be useful on ByteStrings and lazy ByteStrings. Most of these functions are written in terms of Data.List functions or list primitives that have equivolents in Data.ByteString.
So, my question is: is there a clever hack available to me so that I could have 1 version of each function, and have it work on all three different types of input? I'd rather avoid having 3 versions, that are exactly the same except for imports.
People sometimes talk about doing a type class to cover string like modules.
What functions are you thinking of btw? We may want to include them in the ByteString modules anyway (possibly directly rather than in terms of other functions, to take advantage of tricks with the representation).
Spencer Janssen is actually working on such a class (String) to deal with this, initially to support [a] and Word8 and Unicode bytestrings, as part of his Summer of Code project. Note also that we have the Foldable and Monoid classes, which support parts of a String interface. -- Don