Test if a procedure was called as a function, ie x = command(y)
| CALLED_AS_FUNCTION | Test whether a procedure should alter its parameters |
example:
# Procedure which checks how it is called PROCEDURE double PARAMETERS w=workspace RESULT wres IF Called_as_function() # leave the parameter untouched wres = w wres.y = w.y * 2.0 ELSE # change the parameter w.y = w.y * 2.0 ENDIF ENDPROCEDURE
This procedure is very important for a language which allows procedures to be called either as functions returning results or as keyword commands where the paramters are affected. For example, with the Rebin() command, it may be called either as
w = rebin( s(1), ... )
where the last thing we would want to do is replace the value "s(1)" with the result of the rebinning. Alternatively we could type
Rebin w ...
where of course, we would expect to change the contents of workspace "w".
If this check is not made a sequence of functions could produce unexpected results, for example
>> x = bad_rebin(w, v.x) >> y = bad_rebin(w, v.x) >> printn (x=y) $FALSE
RESULT = (Boolean)
Returns $TRUE if the currently executing procedure was called as a function.