comp.lang.idl-pvwave archive: archive » Re: IDL 5.2 array definition question.

Home » Public Forums » archive » Re: IDL 5.2 array definition question.

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: IDL 5.2 array definition question. [message #21428]

Mon, 28 August 2000 00:00

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

Paul van Delst <pvandelst@ncep.noaa.gov> writes:
> The documentation (that I read before posting the original message)
> actually specifies this except the number that they guarenteed across
> versions was only 25!. My (badly formed) question can be rephrased as:
>
> why?
>
> Like I alluded to previously, IDL 5.3 raised the limit to 65536 (or
> thereabouts) which is way larger than any array initialisation anyone
> would want to type by hand, but I would still like to know what design
> decisions the pre-5.3 behaviour was based on. That's all.

My guess is that this is a limitation of the IDL parser, the part of
IDL that converts tokenized text into the compiled form.

Most modern parsers today are written with assistence from programs
like lex and yacc. These parsers *can* have problems handling large
lists of items, but not if they are written properly. In principle
they can handle lists of unbounded size.

I would further guess that the IDL parser is more home-brew than
yacc-descended, and as such has some hardwired limits for things like
array size. They probably just bumped up those limits for IDL v5.3.

Craig

--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------

Report message to a moderator

[Message index]

		Re: IDL 5.2 array definition question. By: Craig Markwardt on Mon, 28 August 2000 00:00
		Re: IDL 5.2 array definition question. By: Paul van Delst on Mon, 28 August 2000 00:00
		Re: IDL 5.2 array definition question. By: davidf on Mon, 28 August 2000 00:00
		Re: IDL 5.2 array definition question. By: Paul van Delst on Mon, 28 August 2000 00:00
		Re: IDL 5.2 array definition question. By: Craig Markwardt on Sat, 26 August 2000 00:00

Previous Topic:	Re: Sum along diagonals
Next Topic:	Re: Origin of IDL

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Nov 28 13:37:57 PST 2025

Total time taken to generate the page: 0.16305 seconds