From: ahoward <ahoward@...>
Date: 2003-02-12T04:20:21+09:00
Subject: Re: Range#length?!?!?

On Wed, 12 Feb 2003, Yukihiro Matsumoto wrote:

> Interesting.

is that good, or bad?  ;-)


> But 'even this' never reaches 'works quickly' under the current
> String#succ behavior.
>
>   for x in 'even this' ... 'works quickly'
>     ...
>   end
>
> would be an infinite loop.

thechnically so is

  for x in 0.0 ... 42.0
    ...
  end

just because one can designate the beginning and ending of range doesn't mean
one MUST be able it iterate over it does it? (asking)

i guess the question is WHAT a Range of strings is :

  * all possible comibnations between start and end
  * a linear (succ) progression between start and end

it seems as if viewing the bytes (mulibytes) of a string as base 256 (or
sizeof multibyte) digits would allow your example to iterater properly since
semantically once you incremented

  'even this'

upto

  'w\000\000\000\000\000\000\000\000\000\000\000\000\000\000'

you could then begin incrementing only [1..-1] untill you had

  'wo\000\000\000\000\000\000\000\000\000\000\000\000\000'

you could then begin incrementing only [2..-1] untill you had

  'wor\000\000\000\000\000\000\000\000\000\000\000\000'


eg. the Range 'foo' ... 'bar' represents all the words greater than or equal
to 'foo' but less than 'bar'.  this seems to make some sort of sense doesn't
it?

perhaps i'm overlooking something here...

so i guess i am reccomending that succ stay the same, but that iteration of
string Ranges use my algorithim to generate all words > or == to start and <
end (iff exclusive?).


> Do you want to change how it works (to something doesn't work for
> multibyte characters)?

couldn't one simply substitute 256 -> sizeof(byte) and maintain my original
algorithim?

> |it also seems to make perfect sense for Float Ranges to have size Infinity?
> |this would suprise no one.
>
> On the contrary,
>
>   for x in 0.0 ... 42.0
>     ...
>   end
>
> stops.

confused ??

irb(main):001:0> for x in 0.0 ... 42.0; end
TypeError: cannot iterate from Float
from (irb):1:in `each'
from (irb):1

-a


-- 

 ====================================
 | Ara Howard
 | NOAA Forecast Systems Laboratory
 | Information and Technology Services
 | Data Systems Group
 | R/FST 325 Broadway
 | Boulder, CO 80305-3328
 | Email: ahoward@fsl.noaa.gov
 | Phone:  303-497-7238
 | Fax:    303-497-7259
 ====================================