sinc(x) -- defining evaluating and simplifying operations

Raymond Toy wrote:

> I wanted to define the sinc(x) function:
> 
> (C1) sinc(x) := if (x = 0) then 1 else sin(x)/x;

Stavros Macrakis wrote: 

> There are three problems with that definition.

I don't see anything wrong with the definition. I'd like
to turn the problem around: What would it take for Maxima
to understand such a thing?

If x is undefined, it seems most useful that the
whole conditional should remain undefined. Yet as Stavros
points out, "Maxima doesn't really handle unevaluated 
conditionals at all". This seems like an area that 
could be improved, then. What is needed to get Maxima
to handle unevaluated conditionals?

That "=" is the wrong kind of equality, seems simply
capricious; but I'll leave that aside for now.

For what it's worth,
Robert Dodier


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