newRPL: symbolic numbers

[Gilles]

All of this looks _very_ interesting...

About EVAL I would prefer to keep the EVAL of 50G and add a EVAL1 command.(that means you have to detect 'circular reference' to avoid infinite loop like X refer to Y wich refer to X ).

I think that it will be interesting for the future to distinguish internaly functions and programs (a functions returns a numeric or symbolic output). For example your n. notation make sense for function but not for program.

Perhaps you could totaly avoid something like the flag 3 of the 50G.
But I see one disavantage (?) in this : If your function is defined in symbolic

f : << -> x '3*x+5' >>

it will always return a symbolic result, unless you use the f. syntax whereas the 50G fonctionality depends of the flag 03

Not sure it's better or worse, but it will be different and if we only want to work with numeric results (and dont use the f. syntax) we could do

f : << 3. * 5. + >>
or
f : << -> x '3*X+5' ->NUM >>
or
f : << -> x '3.*X+5.' ->NUM (or EVAL ) >>