| Keyword checking [message #31015] |
Wed, 29 May 2002 06:20 |
Randall Skelton
Messages: 169
Registered: October 2000
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Senior Member |
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I have run into a great deal of trouble checking keywords in IDL and I
thought I would relay my thoughts and frustrations. I am trying to
prevent a user from passing an undefined variable in a keyword...
Imagine,
pro test, A=a, B=b
print, n_params()
print, arg_present(a), keyword_set(a), n_elements(a), size(a,/type)
print, arg_present(b), keyword_set(b), n_elements(b), size(b,/type)
end
If I call this routine as:
IDL> .reset
IDL> test, a=1, b=undefvar
% Compiled module: TEST.
0
0 1 1 2
1 0 0 0
So, in order to prevent a user from passing junk in a keyword, I have:
pro test, B=b
if n_elements(b) eq 0 and arg_present(b) eq 1 then $
message, 'You passed an undefined variable as a keyword'
if n_elements(b) gt 0 then b = 'passed'
end
Now,
IDL> .reset
IDL> test, b=junk
% Compiled module: TEST.
% TEST: You passed an undefined variable as a keyword
Surely there must be something simpiler than my 2-step approach ;)
Cheers,
Randall
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