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cyrille de brébisson · 10-01-2015, 05:50 AM

Hello,

In the CAS world, it is OK to use undefined variables names. That is after all what the cas is and does.

In the Numerical world, it is not. Everything has to be declared (like in C) and have a value.

In order to make use of both system as easy as possible, the 2 systems are made to look as similar as possible, with functions bearing the same name doing (to the extent that it make sense) the same things.

expr ("'rasp'") in cas will parse the quote(rasp) which will non evaluate the rask identifier/varaible name.

expr ("'rasp'") in NUMERICAL (Non Cas programs are Numerical) will attempt to parse rasp, find it non declared and result in an error.

Both system are VERY powerful in their own domains, created to allow a VERY easy transition from one to the other. Are able to use/communicate/interact, BUT they have some fundamental differences, which are not always evident at first sight and which can be surprising/frustrating for someone transitioning from beginner to advanced user (It is even sometimes surprising for advanced users!).

Prime would be simpler if only one of the 2 modes existed, BUT it would not be Prime, a very versatile system able to takle most use cases.

I hope that this helps and that you can complete whatever you were trying to achieve.

Cyrille