Re: Avoiding side effects

[Anders Wirzenius <anders@no.email.thanks.invalid>]

"(see below)" <yaldnif.w@blueyonder.co.uk> writes:

> On 07/10/2008 15:47, in article uprmc4g3i.fsf@no.email.thanks.invalid,
> "Anders Wirzenius" <anders@no.email.thanks.invalid> wrote:
> 
> > "(see below)" <yaldnif.w@blueyonder.co.uk> writes:
> > 
> >> On 07/10/2008 12:08, in article wvbrfxn8hdc7.fsf@sun.com, "Ole-Hjalmar
> >> Kristensen" <ole-hjalmar.kristensen@substitute_employer_here.com> wrote:
> >> 
> >>> Yes, I think any program which use a read/write interface to a file
> >>> will have side effects in that sense. The only way I can think of for
> >>> avoiding this would be to mmap the whole file, then it will appear as
> >>> an array of bytes.
> >> 
> >> Why would stepping through an array not be thought a "side" effect?
> > 
> > A function that returns the row of that array and only that
> > would perhaps be a function without side effects. The information
> > in that row can be fetched when needed.
> 
> A function that always returns the same row of an array would be of little
> use, I should think.

I have a feeling that the function can be programmed so that it returns
different row (numbers, or pointers in that array) depending on
the content of the rows in that array ;-)

function Row_Number (Row_Number_In_Other_Array : in
                     Row_Number_Type)  return Row_Number_Type is
   --  Return a row number one higher than the row number of the row
   --  identical to the row in the other array. 


-- 
Anders