arg() crashes the emulator

[Han]

(Assuming CAS view)

f(x):=x^2;
f; // returns (x)->(x^2)

lname(f); // returns [ x ]

If you want to make your own program to do what you want to do, you can use the string() function which converts objects into character strings.

fs:=string(f); // convert f into a string
rp:=instring(fs,")"); // find the first ) char
fs:=mid(fs,2,rp-2); // get (rp-2) characters starting at position 2
fpar:=CAS(fs); // convert var list into { var1, var2, ..., varn }

You can use list2mat() if you want fpar to be enclosed by []'s.

This is essentially the same as lname(). (Note lname() is limited to user CAS functions.)