Warp wrote:
> Orchid XP v7 <voi### [at] devnull> wrote:
>> The nice thing about Haskell is that is *allows* you to come up with a 
>> better implementation and slip it in there later.
> 
>   Is that really so? Can you refactor an existing solution (eg. in a library)
> so that it will be more efficient (eg. memorywise) without breaking any
> existing programs?

It depends on the library, and how carefully it was thought out in the 
first place. (I imagine this applies in most languages.)

For example, there is a current project to introduce 
trippy-new-killer-feature "stream fusion". This involves rewriting 
almost *all* the standard Haskell list processing functions (of which 
there are a fairly mind-blowing number) so that they work completely 
differently internally.

Obviously, these are the most-used functions in all of Haskell [three 
guesses why they're being optimised?], and any change to the interface 
would break practically every Haskell program ever written. And breaking 
almost every Haskell program ever written would be a Very Bad Thing(tm). 
Fortunately, they haven't needed to...

Can the same be said for *every* library? Well, that is a harder 
question to answer. My guess would be "many of them", but I don't have 
any really scientific proof of that.

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