Inconsistency when using previously defined variables as arguments to functions


On Sun, 30 Jan 2011, Ilya Ryabinkin wrote:

 
< A similar issue would appear if you try to define a differential
< operator that transforms a function into its derivative. I spent a lot
< of time figuring out how it could be done; the only working way I
< found was quite an awkward construction
<   D(f):=
<   funmake('lambda,
<           [['x], diff(f('x),'x)]);
< Again, this happened because you have to perform differentiation with
< respect to a formal argument, not a variable "x".

This solution is not foolproof:

D(lambda([t],x+t));
 ==> lambda([x], 2)

The foolproof solution would use a gensym, but the answers would not
look so nice.

The problem is that mathematical functions are really 2nd class objects
in Maxima.

Leo

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