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If you want to get a list of all the operands Maple thinks there are in an expression, do op(s). Using this
op notation, you can dig down into a very complex Maple expression and extract any sub-expression you
want. You just do it recursively: a = op(2,s); b = op(7,a); and so on.
Suppressing function arguments
Example 1: Sometimes it is necessary to display arguments of a function to make things "work right", but
then in the result one might prefer not to see the arguments. Consider:
When the undefined function f has no explicit arguments, the deferred Diff differentiations activated by
the value statement give the result 0 since Maple assumes f is a constant. This is repaired by changing f to
f(x,y). If expressions are long and/or there are many arguments, it might be desirable to suppress these
arguments in a final result, and the above shows one way to do this by extracting the function name using
the op command. See elsewhere in this document for comments on Diff, value, % and subs.
Example 2: This fancier example illustrates several things at once: how to get nice subscripts on a vector
function, how to tell Maple not to throw out derivatives of unknown functions, and how to get Maple to
suppress function arguments after they have been explicitly added. It is the suppression of the arguments
that involves the "op" command which is used below to "pick off" just the function name as op 0, causing
the arguments of the function to go away, as in the previous example. Things are very delicate because
Maple always wants to compute derivatives of things which it often interprets as constants. One
constantly has to tell Maple to "defer" evaluation by various methods. One is by using Diff instead of diff
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