OpenEuphoria

Re: Interesting Experiment With String/Sequence Slicing

• Posted by slie at theage.fairfax.com.au Aug 20, 2001
• 405 views

hi Robert,

sorry to keep bring this issue up as the program i am writting
seems to be severely affected by the slowness in the string slicing
function in euphoria.  the program i'm working on is basically doing a lot
of string
string and replace (for large text files) which relies much on the string
slicing.
i am just curious as to ways the program can be optimised and i have
run out of avenues except looking how i can get around the slicing issue.
in my last email i wrote :

>>my conclusion from this test is that the either the slicing or the
>>allocation method in the interpreter is 'iterative' as opposed to just
cutting and
>>moving large chunks of string around in the memory, which explains the
poor perfomance?

i am just wild guessing here, but could it be true that a function can be
specifically written to deal with string type sequences and so speeding up
the slicing function?

regards,
sam lie
Down Under, Australia



----- Original Message -----
From: "Robert Craig" <rds at RapidEuphoria.com>
To: "EUforum" <EUforum at topica.com>
Sent: Friday, August 17, 2001 2:23 AM
Subject: Re: Interesting Experiment With String/Sequence Slicing


>
> slie writes:
> <several examples of slicing>
>
> Without going through your examples in detail,
> I'll just give you a few hints:
>
> 1. Whenever you see:
>
>          x = y
>
>      nothing happens except for a pointer being copied.
>      and maybe a reference count being incremented.
>      If y is a sequence, x and y will now point at a single
>      copy of the same sequence.
>
> 2. When you see:
>
>      y = x[a..b]
>
>      Then the data from a to b is copied and a new sequence is
>      created. (Back in v1.4 and earlier I used to just have y point at the
data
>      in x that it needed, but I later changed this).
>
> 3. When you see:
>
>      x = x[a..b]
>
>     and there are no other references to the sequence,
>     then I simply adjust the pointers to the beginning and end of x,
>     without copying anything. If I am left with a huge amount of
>     unused space, then I might decide to free it up.
>
> Regards,
>    Rob Craig
>    Rapid Deployment Software
>    http://www.RapidEuphoria.com
>
>
>
>
>
>



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