newRPL - build 1255 released! [updated to 1299]

[Claudio L.]

(04-04-2018 11:53 PM)The Shadow Wrote:  So given that we stored 5 in C like you said, if we then changed B to 3, C would change to 4 and D to 16, right?

Correct.

(04-04-2018 11:53 PM)The Shadow Wrote:  EDIT: How does one examine the properties of a variable?

Just RCL the name of the property:

Code:

'C...Defn' RCL

(04-04-2018 11:53 PM)The Shadow Wrote:  And how do the attributes of identifiers differ from properties?

Attributes are flags (on/off) that are stored with an identifier, not necessarily with a variable.
Properties are like hidden variables that can contain objects and are stored in the same directory as their "owner" variable. They are purged when the main variable is purged.
Attributes are part of the identifier object (a 32-bit word, so up to 32 flags). This will in the future be used for the CAS, for example to do REALASSUME on a variable in an expression, it is enough to set the attribute on every appearance of the identifier in the expression, so even though the variable may not exist, the CAS knows it's a real variable, and that knowledge is embedded in the symbolic expression. Another use may be for example a flag that marks a variable as a Matrix (within an expression), therefore the CAS can never use the commutative property of multiplication to simplify a formula, for instance INV(A)*B*A could be simplified as B unless you specifically set A attribute as a Matrix (EDIT: and B as a Matrix as well, if B is marked as real, then the CAS should simplify to B*I, but you get the idea) .

(04-05-2018 04:21 AM)The Shadow Wrote:  If C initially has a Defn of 'A+B' and I later change it to 'A+P', I assume the dependency is removed from B?

Correct.

(04-05-2018 04:21 AM)The Shadow Wrote:  Does that mean the calculator first scans 'A+B' to determine what to remove, then scans 'A+P' to determine what to add? So A gets altered twice?

No, they way I implemented (just finished that yesterday) there's a single modification of A. I exploded 2 lists of variables: the old dependencies and the new dependencies. I scan the old dependency list, get all items except the variable being removed, then check if the variable is also in the new dependency list, add it at the end and then store the new dependency. At this point the variable is removed from the new dependency list.
Then it goes over the new dependency list (or what's left of it) to take care of dependencies that are new.

(04-05-2018 04:21 AM)The Shadow Wrote:  EDIT: Oh! Are tagged objects just going to be a property or attribute now?

No, the tag hasn't been implemented yet, but will be similar/compatible with the 50g. Just an object that contains a tag and an object.

(04-05-2018 04:21 AM)The Shadow Wrote:  Can the user create new properties, or are they all hard-coded?

Yes, you are free to create any properties. A few names like 'Defn', 'Depn', 'Unit', and possibly others have a specific use by the system (you are still free to purge them and manually modify them at will, and at your own risk). The logic and use of them is up to the user.

(04-06-2018 06:00 AM)pier4r Wrote:  Uh. All those years and I was mislead by few experiences I made. I just tested it myself and you are right . Somehow I completely forgot how symbolic holds. And yes the system goes through the variables as well. Amazing feature that I failed to see.

That for formulas or systems is awesome. Rpl never stops to amaze me.
And wonder if the Casio/ti do the same.

Yes, there's nothing wrong with the old ways, and they will remain as-is on newRPL too. Nothing has or will change that, the user won't feel any difference unless they explicitly choose to store a formula as the 'Defn' property on a variable rather than the variable itself.

(04-06-2018 06:00 AM)pier4r Wrote:  The only difference with the idea of Claudio is that you need to explicitly eval this or that variable, instead with Claudio's idea you get the computation immediately

Exactly, the new method creates quick templates for repetitive problems, even from the VARS menu, you change a variable typing the new value and using Shift-[menu key] to store it, and instantly see the various results by pressing another menu key, really practical, one keystroke.