Re: something like perl's 'require 5.4'

[Paul van Delst <paul.vandelst(at)noaa.gov>]

JD Smith wrote:
> 
> Craig Markwardt wrote:
> >
> > Vapuser <vapuser@catspaw.jpl.nasa.gov> writes:
> > >   How about:
> > >
> > >   version=strupcase(strjoin(strsplit(!version.release,'[.-_]',/extract),""))
> > >   input_version=strupcase(strjoin(strsplit(desired_release,'[.-_]',/extract),""))
> > >   if version lt input_version then 'eeek'
> > >
> > >   Clearly `desired_release' would have to be input as a string.
> > >
> > >   Of couse, this method 'requires' IDL 5.3 (IIRC), to get the regular
> > >   expression semantics of strsplit. The other question is will RSI use
> > >   any separator in version designations besides these three?
> >
> > Umm, I never thought I'd be saying this, but aren't these a bit
> > overengineered?  I have found that in 95% of the cases the DOUBLE
> > compare will work, and in 4% of the cases the STRING compare will
> > work.
> 
> *cough*
> 
> <REITERATE>
> 
> IDL> print, double('5.4.1') gt 5.4
>    0
> 
> </REITERATE>

wot about

IDL> print, double('5.4.1') ge 5.4d0
   1

?

Doesn't assuage your other concerns regarding the significance of the last digit however.
I use comparisons like the above for code that contains BREAK, CONTINUE, SWITCH, etc
statements. Or similar for the version in which pointers and objects were introduced (5.2?
can't remember).

I think it would be pretty difficult (for unsophisticated ol' me) to maintain code that
contains version tests for when RSI fixes a bug -- like in the examples you listed....
although, HISTOGRAM and REBIN? Never use 'em. :o)  What _possible_ use could they be?? 
(*).

paulv

(*) sarcasm alert for the irony impaired

-- 
Paul van Delst           A little learning is a dangerous thing;
CIMSS @ NOAA/NCEP        Drink deep, or taste not the Pierian spring;
Ph: (301)763-8000 x7274  There shallow draughts intoxicate the brain,
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paul.vandelst@noaa.gov                   Alexander Pope.