Re: [Haskell-cafe] Is the #functional programming paradigm antithetical to efficient strings? #Haskell

On 07/11/2016 04:28 PM, Stephen Tetley wrote:

On 11 July 2016 at 13:54, David Fox wrote:

...

When I mentioned some of this, I was told "different data structures for different purposes", which sort of makes sense, but honestly if Haskell is a language where you have to sit down and choose a representation every time you want to build some text, I get a bit discouraged.

Don't C# and Java have StringBuilder classes (different to their regular String types) for this as well?

Yes, they do. If you just naively do String s = ""; for (int i = 0; i < 1000000; i++) { s = s + "hello"; } in Java you'll also get terrible performance (O(n^2)) as opposed to the equivalent code using StringBuilder which would be O(n). This does not change if you use e.g. Text/ByteString/Vector in Haskell. In Haskell, I could certainly imagine List[Char] being more performant than copying huge chunks of memory over and over... even though List traversal *is* generally slow. (Of course the actual performance depends on lots and lots of specifics.)

Maybe imperative OO is also antithetical to efficient strings...

Bad algorithms and data structures are antithetical to efficient strings :). Regards,