CAS command question

[DrD]

Hi Han!

Thanks for your insight.

First point, would you think that the internal representation is known by the typical prime programmer, or that it even should be an important factor for a relatively high level language programming environment?

Second point, I understand your thinking here. However, when the need arises, especially after some time has elapsed, a program designed to gather expressions just as they are encountered seems more practical. So requiring them to be re-written to accommodate an inequality sign 'convention' is needless extra work, and one more place for user inputs to go wrong. Not to mention that a user's mindset is probably more focused on problem solving, and simplifying the solution task is important.

Third point, It's true, inequalities are omitted, specifically. However the command set is not rich in this area, and apparently giac does further extend those commands to strings, (I used strings in the example). More than once I have needed to separate expression relations for further activities, so a command that would be able to do that has value.

Your last point IS the issue. You've identified the fact that the current command set DOES complicate programs using this technique. I think the prime could be improved by restructuring the left() and right() commands, returning the left or right side of any expression, without performing an evaluation first. A (possible) exception might be, IF the expressions are strictly numerical: 2+2 < 5., but why?

-Dale-