HP Prime Graphing Calculator - Manual (Page 521)

Programming 517
You can even get the program to return user-defined
functions as well as system functions, and user-defined
variables as well as system variables.
You can also re-assign a shifted key combination. So, for
example,
ASn could be re-assigned to produce
SLOPE(F1(X),3) rather than the lowercase t. Then if
ASn is entered in Home view and E
pressed, the gradient at X = 3 of whatever function is
currently defined as F1(X) in the Function app would be
returned.
T i p A quick way to write a program to re-assign a key is to
press Z and select Create user key when you are
in the Program Editor. You will then be asked to press the
key (or key combination) you want to re-assign. A
program template appears, with the internal name of the
key (or key combination) added automatically.
Key names
The first line of a program that re-assigns a key must
specify the key to be reassigned using its internal name.
The table below gives the internal name for each key.
Note that key names are case-sensitive.
Internal name of keys and key states
Key Name S
+ key
A
+ key
AS
+ key
N K_0 KS_0 KA_0 KSA_0
x K_1 KS_1 KA_1 KSA_1
y K_2 KS_2 KA_2 KSA_2
z K_3 KS_3 KA_2 KSA_2
t K_4 KS_4 KA_4 KSA_4
u K_5 KS_5 KA_5 KSA_5
v K_6 KS_6 KA_6 KSA_6
p K_7 KS_7 KA_7 KSA_7
q K_8 KS_8 KA_8 KSA_8
r K_9 KS_9 KA_9 KSA_9