| Re: axis problem [message #35776 is a reply to message #35775] |
Sun, 20 July 2003 13:42   |
R.Bauer
Messages: 1424
Registered: November 1998
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Senior Member |
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David Fanning wrote:
> Reimar Bauer writes:
>
>> David I can't agree
>>
>> It can't be that the user program has to test what keywords values are
>> set as default by a routine and if it has this value then it must be
>> killed from the _extra structure if it is there.
>>
>> With all the other keywords it works as supposed. It would be very bad
>> if it is somewhere defined that's the user is not able to pass default
>> values by _extra. It must be possible to switch back to the whatever
>> default value by submitting 0 for example.
>>
>> At the moment I believe there is a bug with the querying of xyz minor.
>> They used keyword_set() instead of n_elements() and ...
>
> I'm not so sure of my answer that I would bet a
> whole lot of money on the "no bug" theory, but still...
>
> Think of how you would do this. A keyword has a value of 5 by
> default. If the keyword is set to 0, you which to set the
> value to 5. You would write the program like this:
>
> PRO MyPlot, KEY=key, _Extra=extra
> IF N_Elements(key) EQ 0 THEN key = 5
> IF key EQ 0 THEN key = 5
>
> PLOTSOMETHING, Key=key, _Extra=extra
> END
>
> Now, if you pass a value in with the keyword, you encounter
> the "processing".
>
> IDL> MyPlot, KEY=0
>
> If you pass it in via the _EXTRA mechanism, you bypass
> the processing:
>
> IDL> MyPlot, _Extra={KEY:0}
>
> This seems quite reasonable to me. The alternative would
> be to put something like this into your program:
>
> IF N_ELements(extra) NE 0 THEN BEGIN
> tagnames = Tag_Names(extra)
> index = WHERE(tagnames EQ 'K', count)
> IF count GT 0 THEN IF extra.(index) EQ 0 THEN key = 5
> index = WHERE(tagnames EQ 'KE', count)
> IF count GT 0 THEN IF extra.(index) EQ 0 THEN key = 5
> index = WHERE(tagnames EQ 'KEY', count)
> IF count GT 0 THEN IF extra.(index) EQ 0 THEN key = 5
> ENDIF
>
> Think what would happen if you wrote a long keyword name,
> or if you had multiple keywords defined that you had to
> chase down like this. You would spend all your time writing
> code and no time at all drinking beer. :-(
>
> Cheers,
>
> David
Dear David,
I think they have probably written a function like this,
FUNCTION is_keyword,keyword,names
ix=where(strpos(names,keyword) eq 0 ,count_ix)
if count_ix eq 1 then return,names[ix]$
else message,'Ambiguous keyword abbreviation '+keyword,/cont
end
And with routine_info you get the names of the keywords of the routine
But I can't do this myself with plot
print,is_keyword('xmin',['xminor','xaxis'])
xminor
print,is_keyword('x',['xminor','xaxis'])
print,is_keyword('x',['xminor','xaxis'])
% IS_KEYWORD: Ambiguous keyword abbreviation x
0
Let us have the next beer
Prost
Reimar
--
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
http://www.fz-juelich.de/icg/icg-i/
============================================================ ======
a IDL library at ForschungsZentrum Juelich
http://www.fz-juelich.de/icg/icg-i/idl_icglib/idl_lib_intro. html
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