10-25-2015, 11:31 AM
Post: #94
 Han Senior Member Posts: 1,877 Joined: Dec 2013
(10-25-2015 01:52 AM)Claudio L. Wrote:
(10-24-2015 08:30 PM)Helix Wrote:  I'm not sure I undestand what you mean. An identifier without quotes is evaluated immediately. Could you give a short example of what you think?

Yes, but the quotes work only when the identifier is by itself, not inside an expression. The idea is that 'X.+2' evaluates X immediately, because the user "requested" it by adding the trailing dot.
There should be a command to make certain variables in an expression evaluate, perhaps:
'X^2+Y' 'Y' ->EVALNOW would produce the expression 'X^2+Y.' which would cause Y to be evaluated immediately next time the expressions is executed or operated upon. If Y is 4, then:

'X^2+Y' 1 + --> 'X^2+Y+1'
'X^2+Y.' 1 + --> 'X^2+5'

In the second case, only the Y was evaluated automatically, X will not be evaluated unless EVAL is called on the expression.

What I meant is that the name ->APPROX doesn't really work for variables, should be something like the EVALNOW above.

While I think the "dot" notation is nice for immediate evaluation, it really seems to be contrary to the whole notion of RPN.

'X^2+Y' 1 + --> 'X' SQ 'Y' + 1 +
'X^2+Y.' 1 + --> 'X' SQ Y + 1 +

But even with the feature, I am not sure it would be used as described. If I wanted immediate substitution, I imagine that I would still end up double checking the value of Y prior to having the calculator actually include it into a formula. So a quick RCL of the contents of Y would most likely occur -- and at this point I may as well just build my formula with the Y value already on the stack.

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