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

On Mon, Jul 11, 2016 at 2:09 PM, Bardur Arantsson wrote:

On 07/11/2016 02:54 PM, David Fox wrote:

...

On Sun, Jul 10, 2016 at 11:44 AM, KC mailto:kc1956@gmail.com> wrote:

Is the #functional programming paradigm antithetical to efficient strings? #Haskell

​I can certainly see how it might seem so. Our main string representation​ uses about 10 times more memory than seems necessary, and is relatively fast, though probably not compared to C. Recently I spent some time looking into how to reduce this memory overhead, and I modified the pretty library (https://github.com/ddssff/pretty/tree/textdetails) so it could use any type that was an instance of ListLike and StringLike (https://github.com/JohnLato/listlike https://github..com/JohnLato/listlike). Then I tried the UnitLargeDoc test with several different data types. This just concatenates a list of ten million "Hello" strings. Using String this happens in about 5 seconds. Using strict or lazy Text it immediately blew the stack. When I increased the stack size to over 1GB it took minutes to complete. When I used the Data.Text.Lazy.Builder type instead it took about 30 seconds to complete. Results with utf8 encoded ByteStrings were siimilar.

Did you try similar code on Java/C# (or whatever)?

​I did not.​