| Re: Technique for "method_missing" in IDL objects [message #67254] |
Fri, 17 July 2009 11:15  |
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Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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mankoff wrote:
> On Jul 17, 12:20 pm, Paul van Delst <paul.vande...@noaa.gov> wrote:
>> Hello,
>>
>> I'm stringing together a bunch of different objects into a container. When I define
>> objects I always define an "Inspect" method so I can have a lookee at the internals of the
>> objects (like the ruby inspect method). However, the inspect method for the container
>> simply loops over the objects that have been placed in it calling their inspect methods.
>> So, if I reach an object that does not have an inspect method, is there a technique to
>> pre-determine if I can even call the method to avoid the
>>
>> % Attempt to call undefined procedure/function: 'OBJ::INSPECT'
>>
>> error that I get?
>>
>> Ruby provides a "method_missing" method to enable one to handle this sort of thing. Does
>> IDL have any sort of equivalent? Looking at the various ROUTINE_INFO, RESOLVE_ROUTINE
>> help, they don't appear to be that reliable.
>>
>> cheers,
>>
>> paulv
>
> If a top level object has an INSPECT method, then it will always be
> found in a parent. I'm not sure if IDL objects have this ability, but
> can the top level INSPECT check to see if it was called by itself or a
> child? If so, and you never call it explicitly, then if a child is
> running the top level INSPECT it implies the child does not have its
> own INSPECT.
Umm... not sure I follow. FWIW, here's my container Inspect method:
PRO LBL_Input::Inspect, $
Verbose=Verbose, $ ; Input keyword
Debug=Debug ; Input keyword
IF ( KEYWORD_SET(Debug) ) THEN HELP, /ROUTINES
HELP, self, /OBJECTS
IF ( KEYWORD_SET(Verbose) ) THEN BEGIN
obj = self->Get(/ALL, COUNT=n_Objs)
IF ( n_Objs EQ 0 ) THEN RETURN
; Loop over contained objects
FOR n = 0L, n_Objs-1L DO BEGIN
obj[n]->Inspect, Verbose=Verbose, Debug=Debug
ENDFOR
ENDIF
END ; PRO LBL_Input::Inspect
And it's the call to the individual object inspect methods in the loop,
obj[n]->Inspect, Verbose=Verbose, Debug=Debug
that can cause the constipation. I changed the above line to
IF ( OBJ_HASMETHOD(obj[n], 'INSPECT') ) THEN $
obj[n]->Inspect, Verbose=Verbose, Debug=Debug
and now all is wonderful! Woohoo!
:o)
cheers,
paulv
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