newRPL: symbolic numbers

[Claudio L.]

(12-23-2014 12:06 PM)Nigel (UK) Wrote:  Suppose I have an expression 'r=d/2'. If I store '7' or '7.0' (both quoted) in d, I'd expect to get 7/2 for r when this expression is evaluated. If I store 7.0, I'd expect to get 3.5 and not 7/2. I'm not sure what I'd expect if 7 (without the quotes) was stored in d.

That's a good point. Being that 'r=d/2' is a symbolic expression, once the number is replaced inside the expression, there's no way to tell if it came from a number or a symbolic number, so it would always return 'r=7/2' (doesn't matter if it's 7 or 7.0 in this case).

(12-23-2014 12:06 PM)Nigel (UK) Wrote:  My point is that real numbers or numbers in standard form are generally not intended to be exact. Unless they are deliberately quoted they should stay approximate, even if they appear inside a quoted expression. If this is what you intend your idea seems excellent.

You raised a very good point. Replacement inside an expression would always convert a number into symbolic. This differs from the current status-quo but then, if you are manipulating symbolic expressions, why shouldn't it be symbolic?
You are expecting 'r=3.5' and not 'r=7/2' , but is this only a consequence of how the 50g works (that makes you expect that), or a standard in other mathematical software?.
Does anyone know if any other calculators or math software behaves that way?