CAS command question

[DrD]

The topic is pretty well covered now, and my own parting thoughts are that the CAS left/right commands are just not fully implemented.

Parisse has alluded to the fact that in the left(), right(), string objects are part of giac, but not the prime, that inequality relations are not part of the command features, (as per help guides), and that consistency requires evaluation which turns the expressions around whenever "<" operators are embedded.

Support for the status quo can be found in some other CAS products, and support for the counter-approach (left returns left, etc.) can be found as well, in still other CAS products.

Separate commands for left and right, (currently unavailable), could offer a compromise, for those who feel low-level (near machine language) programming is more important than a high-level (interpreted) environment.

As for me, I would prefer a closer analog with the literal language interpretation, as Arno K presented: left returns left for ANY relational operation, etc. This could be an ENHANCEMENT for the existing commands, by taking the existing command's "evaluated" expressions, and TURN them BACK around, (from what has been described as "natural order"). Much less desirable, would be to amend the Help doc's to warn users away from expressions with inequality relational operators.

Thanks, everyone. Evolution isn't so easy, but the end result, hopefully, is worth the pursuit! I appreciate your point of view, and that you took the time to respond.

-Dale-