newRPL - build 1255 released! [updated to 1299]
07-30-2019, 03:12 PM (This post was last modified: 07-30-2019 03:15 PM by JoJo1973.)
Post: #537
 JoJo1973 Member Posts: 104 Joined: Apr 2016
RE: newRPL - build 1255 released! [updated to 1282]
(07-30-2019 02:35 PM)Claudio L. Wrote:  I'd like to open a discussion here:

What would be a good syntax for ASSUME?

The way it used to be, the old CAS would store information in the current directory. Now that information is included within the symbolic expression (see the wiki on symbolic expressions). Now we need a "simple" syntax so the user can make all occurrences of a variable within an expression have the same assumptions (the 3-digit numeric code).
Something along the lines of:
Code:
'X^2+4' 6 'X' ASSUME

Which would make 'X' in the expression known to be a matrix (numeric code 6). But... is there a way to do it without forcing the user to remember those cryptic codes?
Right now the user can type the equation with the codes in it as subscripts, but I'd like to be able to change it after the fact.
I know, this would be ideal for the equation writer: just select the variable and a couple of check boxes appear where you select the type and be done, but that is "in planning stages" still.

What could be a good syntax instead of numeric code?

First, a list of mnemonics, short and easy to memorize, e.g.

Type: "R." Real and finite; "C∞" complex and infinite, etc.
Sign: "≥0", "≠0", etc.
Parity: "OD", "EV"

plus standard codes for "Any" and "Unknown" ("*" and "?", perhaps?)

Then you can collect these mnemonics in a list or a string with separators.

Empty list or string clears assumptions.

Of course there should be a command that given a variable lists its assumptions.
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