When there is a bug, I happily report it or fix it. As do all requests get noted and added (such as to add something like AXL on the 50g which has been on the list for quite a while).
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If a user picks up an RPN only calculator, tries to add "2+2" and it doesn't work, is that a bug? Is it a lack of understanding? Is it unexpected behavior? Is it a design flaw? Is it a marketing failure? What is it classified as?
The sheer number of things being combined into 1 post makes it difficult to respond to them, *especially* when the posts keep being edited and changed. :-|
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rref with a string, seems like a bug to me (then again, wolfram as pointed out does something with it). I've reported it.
concat([[1,2],[3,4]],[4,5]) => [[1,2],[3,4], 4,5 ] is combining a vector of vectors (a matrix) with another vector. Just what happens in mathematica... (http://www.wolframalpha.com/input/?i=join%28[[1%2C2]%2C[3%2C4]]%2C[4%2C5]%29)
However, if the user doesn't understand that there is not any difference between a matrix/vector/list from the perspective of the CAS, then yes it appears to do something wrong and unexpected. However, it is acting consistently and as designed.
The CAS in Prime is supposed to be acting more like maple, mathematica, R, and other "professional" type software packages. This means it should be more attractive in terms of upper education or professional use since it acts like the tools that actually get used!
It does bring the downside that it is more complex and can do some strange things sometimes.
I am trying hard to keep up with the comments. It is a bit hard though due to the sheer volume.
TW
Edited: 24 July 2013, 5:37 p.m.