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Difference between lower and upper case chars in CAS and Home
07-04-2016, 03:16 PM
Post: #2
RE: Difference between lower and upper case chars in CAS and Home
Parisse once wrote:
Quote:The CAS parser was adapted from the Xcas parser (some rules are not available), and the CAS lexer has less keywords than the Xcas parser: for example synonyms were removed unlike in Xcas, where you can sometimes use several keywords for the same command (one is familiar for TI users, one for maple users, etc.). The general rule in Xcas is that you can type a command all lowercase (no need to switch if you type from keyboard). The general rule in Prime Home is that you can type a command all uppercase. Some commands exist in Home uppercase and CAS lowercase that have almost the same functionnality, but not exactly the same: convert is one example, since convert in CAS can also do symbolic conversions. I think that if HP modifies the UI so that commands in the catalog appear in lowercase when called from CAS mode and both commands exist, a large part of the confusions would disappear.

Generally, Home commands are upper case commands, and CAS commands are lower case. You can use either type of command in either view, but many of the CAS command arguments must be handled within quotation marks, in order to work in Home view.

For example:
Suppose you want to solve a transfer function for a certain value in the s-plane. If the transfer function is given as Gp=1/(s+1), it could be entered

[CAS ]


CAS("Gp:=1/(s+1)"); // note quotes

Then you might want, for example, to substitute s=1, in the transfer function equation:

subst(Gp,s,1); // ==> 1/2


subst("Gp,s,1"); // ==>1/2

The example used lower case (CAS) variables, which would not work in Home view. This is a confusing requirement, but as time marches on, perhaps HOME vs CAS operation will become more fluid.

The secret to success is to use the prime often! A great teacher is, (ahem), a mistake!

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RE: Difference between lower and upper case chars in CAS and Home - DrD - 07-04-2016 03:16 PM

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