OpenEuphoria

Re: Sequence of Suggestion (was Re: The Title Should At Least Mention Strings (

• Posted by Pete Lomax <petelomax at blueyonder.co.uk> Jun 02, 2004
• 491 views

On Wed, 02 Jun 2004 08:03:46 +1000, Patrick Barnes
<mistertrik at hotmail.com> wrote:

>But this is what euphoria has to do ALL THE TIME currently. In fact, it's 
>even worse
>than in this example, because at least with this example you only have to 
>check text_picture[3], not the entire text_picture.
Waaay ahead of you there. I once had a program with a huge and
complicated fieldlist table at the centre, which practically every
other line in the whole program updated. Adding type checking to it
dropped the load time from about 2 seconds to around 80!

Here is a contrived example:
atom t0
	t0=time()
type table(sequence t)
	for i=1 to length(t) do
		if not integer(t[i]) or t[i]<-100 or t[1]>100 then return 0
end if
	end for
	return 1
end type
--table t
sequence t
t=repeat(0,10000)
	for i=1 to 10000 do
		t[i]=5
	end for
printf(1,"%3.2f\n",time()-t0)
if getc(0) then end if

Replacing sequence t with table t drops the time from between 0.00 and
0.01 seconds to over 100 seconds, which is some slowdown!

Of course I understand precisely why, and we definitely need some
better way. What amuses me is Rob sounds a little surprised and hurt
that no-one uses user defined types much )

<snip>
>>type textpict_line( sequence s)
>>    if length(s) != 80 then return 0 end if
>>    return 1
>>end type
>>sequence of textpict_line of char text_picture
>>textpict_line somevar
>>	somevar=repeat({0,0},80)		-- OK
>>	text_picture[3]=somevar		-- Erm...
>>
>>Here we assign a textpict_line to a textpict_line, so we don't need to
>>do any type checking right? Wrong, of course.
>
>Uh, why wrong? There would need to be type checking when repeat() is 
>assigned to somevar, but not when somevar is assigned to text_picture.
somevar is just a sequence of length 80, so the repeat assignment is
fine. text_picture[3] should be a sequence of char, of length 80.

<snip>
>type textpict_line( sequence of char s)
<snip>
>Would the above solve other problems too?
Yes, because you have much more naturally associated the 'of char'
with the textpict_line type.
>
>Perhaps once a program has been sufficiently tested, type checking could be 
>turned off for better performance.
That's precisely what without type_check does.

Pete