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Re: IDL 8.0 compile_opt changes [message #69240 is a reply to message #69187]

Mon, 28 December 2009 04:36

wlandsman
Messages: 743
Registered: June 2000

Senior Member

On Dec 24, 11:49 am, pp <pp.pente...@gmail.com> wrote:
The trouble happens if there
> are both a function and a variable with the same name. If the
> reference is found before the function is compiled, it is taken to be
> a variable. If the function happens to have been compiled, the
> reference is taken to be a function. So the conversion of a file does
> not depend only on its contents, but also on the environment when the
> file is read. And as many other topics here indicate, routine name
> resolution is fraught with difficulties.

That ambiguity provides a reminder of why users should use square
brackets for indexing, irrespective of any IDL 8.0 changes. The test
program

pro test
rot = indgen(3)
print,rot(1)
return
end

will treat rot(1) as the ITTVIS rot.pro function, rather than a
variable, but only if it has been previously compiled. The
consistent use of square brackets for indexing removes all ambiguity.

While a program to automatically convert to square brackets won't know
whether a user really wants rot(1) to be a function call or an indexed
variable, it can certainly flag all such ambiguous cases, so that the
user can manually edit them if they don't want the function call.
Such cases should be relatively rare, and one could argue that the
program was broken to begin with.

Incidentally, Bill Thompson had written a converter to square brackets
that was better than mine. (It handled most EXECUTE() strings and
main level programs.) It is available at http://tinyurl.com/yasbr7m

--Wayne

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[Message index]

		IDL 8.0 compile_opt changes By: chris_torrence@NOSPAM on Fri, 18 December 2009 13:51
		Re: IDL 8.0 compile_opt changes By: wlandsman on Mon, 28 December 2009 04:36
		Re: IDL 8.0 compile_opt changes By: penteado on Sun, 27 December 2009 19:44
		Re: IDL 8.0 compile_opt changes By: H. Evans on Sat, 26 December 2009 13:21
		Re: IDL 8.0 compile_opt changes By: alt on Fri, 25 December 2009 02:30
		Re: IDL 8.0 compile_opt changes By: penteado on Thu, 24 December 2009 08:49
		Re: IDL 8.0 compile_opt changes By: wlandsman on Thu, 24 December 2009 05:07
		Re: IDL 8.0 compile_opt changes By: David Fanning on Thu, 24 December 2009 03:44
		Re: IDL 8.0 compile_opt changes By: penteado on Wed, 23 December 2009 22:13
		Re: IDL 8.0 compile_opt changes By: David Fanning on Wed, 23 December 2009 20:48
		Re: IDL 8.0 compile_opt changes By: proffmw@gmail.com on Wed, 23 December 2009 20:08
		Re: IDL 8.0 compile_opt changes By: penteado on Wed, 06 January 2010 10:35
		Re: IDL 8.0 compile_opt changes By: JDS on Fri, 08 January 2010 13:42
		Re: IDL 8.0 compile_opt changes By: Matt[2] on Wed, 06 January 2010 08:18
		Re: IDL 8.0 compile_opt changes By: Yngvar Larsen on Wed, 06 January 2010 07:29
		Re: IDL 8.0 compile_opt changes By: David Fanning on Wed, 06 January 2010 07:13
		Re: IDL 8.0 compile_opt changes By: Yngvar Larsen on Wed, 06 January 2010 07:12
		Re: IDL 8.0 compile_opt changes By: Kenneth P. Bowman on Wed, 06 January 2010 06:52
		Re: IDL 8.0 compile_opt changes By: Yngvar Larsen on Wed, 06 January 2010 06:56
		Re: IDL 8.0 compile_opt changes By: Michael Galloy on Wed, 06 January 2010 13:52
		Re: IDL 8.0 compile_opt changes By: Maarten[1] on Wed, 06 January 2010 06:01
		Re: IDL 8.0 compile_opt changes By: Michael Galloy on Wed, 06 January 2010 13:25
		Re: IDL 8.0 compile_opt changes By: penteado on Tue, 05 January 2010 15:54
		Re: IDL 8.0 compile_opt changes By: JDS on Tue, 05 January 2010 14:41
		Re: IDL 8.0 compile_opt changes By: Paul Van Delst[1] on Thu, 07 January 2010 08:35
		Re: IDL 8.0 compile_opt changes By: monkman on Tue, 05 January 2010 13:51
		Re: IDL 8.0 compile_opt changes By: David Fanning on Tue, 05 January 2010 11:17
		Re: IDL 8.0 compile_opt changes By: chris_torrence@NOSPAM on Tue, 05 January 2010 10:58
		Re: IDL 8.0 compile_opt changes By: chris_torrence@NOSPAM on Tue, 05 January 2010 10:57
		Re: IDL 8.0 compile_opt changes By: pgrigis on Tue, 05 January 2010 06:57
		Re: IDL 8.0 compile_opt changes By: R.Bauer on Tue, 05 January 2010 06:09
		Re: IDL 8.0 compile_opt changes By: David Fanning on Mon, 04 January 2010 11:58
		Re: IDL 8.0 compile_opt changes By: chris_torrence@NOSPAM on Mon, 04 January 2010 11:41
		Re: IDL 8.0 compile_opt changes By: R.Bauer on Mon, 04 January 2010 02:30
		Re: IDL 8.0 compile_opt changes By: Jeremy Bailin on Tue, 29 December 2009 21:31
		Ruby range operators? Re: IDL 8.0 compile_opt changes By: Paul Van Delst[1] on Fri, 08 January 2010 13:16
		Re: IDL 8.0 compile_opt changes By: penteado on Fri, 08 January 2010 05:36
		Re: IDL 8.0 compile_opt changes By: Maarten[1] on Fri, 08 January 2010 04:19
		Re: IDL 8.0 compile_opt changes By: H. Evans on Fri, 08 January 2010 01:29
		Re: IDL 8.0 compile_opt changes By: Michael Galloy on Thu, 07 January 2010 09:56
		Re: IDL 8.0 compile_opt changes By: Maarten[1] on Thu, 07 January 2010 07:27
		Re: IDL 8.0 compile_opt changes By: wallabadah on Wed, 06 January 2010 16:30

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