Re[3]: [cgmo-webcgm] ISSUE: delimited string inconsistency?

[Benoit Bezaire <benoit@itedo.com>]

Friday, May 6, 2005, 10:28:53 AM, Lofton wrote:

LH> At 09:53 AM 5/6/2005 -0400, Benoit Bezaire wrote:
>>Hi Lofton,
>>
>>So are you still convinced that a single string is better than a
>>delimited string for the 'region' attribute? I am not.

LH> Okay, first lets clarify.  If you were going to apply delimited string to
LH> this rectangular region of a single subregion, are you talking about:

LH> "'1 '0' '0' '100' '100'"  or  "'1 0 0 100 100'"   ?

LH> I'm guessing the latter (the first is just a silly waste of quotes),
Yes, the latter. But actually we agree in Munich that delimited string
would only be used if multiple strings are return, else it's a single
string.

LH> so that a rectangular annulus would be:

LH> " '1 0 0 100 100'  '1 25 25 75 75'  "

LH> I.e., each sub-region is delimited.
Yes.

>>It seems like we would be re-inventing a single string syntax for this
>>particular attribute when we've define a syntax to handle these kinds
>>of problems (i.e., delimited strings).

LH> In my view, delimited strings are necessary to handle the "strings of
LH> sub-strings" case, where the sub-strings can contain all sorts of stuff
LH> like blanks, commas, etc.

LH> Region is a list of numbers.  A number is a consecutive string consisting
LH> only of digits, +/- signs, decimal point (and maybe "E", in the case that
LH> we allow scientific notation, -0.6e32 -- haven't thought about this one yet.)

LH> I don't really see what "delimited string" adds to 'region', other than
LH> complexity of syntax.
That's because we you're only thinking about the rectangle type. See
below.

LH> By far the most common region will be rectangle, hence this
LH> region:  1,0,0,100,100
I don't think that's true. Isodraw initially started to support
'region' using polybezier (type 4).

LH> Do we really want,
LH> "'1 0 0 100 100'"  (or "'1' '0' '100' '100'")?
Neither, we agreed to: "1 0 0 100 100" (in Munich).

LH> To me, even a multi-sub-region is dead simple to handle:

LH> " 1 0 0 100 100  1 25 25 75 75  "
Now do the same exercise with type 3 and/or 4, and you'll notice it
doesn't work. Type does _not_ tell you how many points there are, not
for polygon and polybezier.

I don't feel like writing code to figure out what this is suppose to
be :)
"3 0 0 100 0 100 200 0 200 4 0 0 0 0 100 0 100 0 100 0 100 200 100
200 100 200 200 0 200 0"

LH> I guess I could live with it either way, but don't see any reason to apply
LH> more powerful syntax to a simple problem like region.
I'm thinking we don't have much of a choice, it has to be a delimited
string (for multiple sub-regions).

LH> Cheers,
LH> -Lofton.

Regards,

-- 
 Benoit   mailto:benoit@itedo.com