HP Prime crashes on undef-undef*i in CAS

[Albert Chan]

(12-01-2020 07:59 AM)parisse Wrote:  Now that it is reported we will of course do our best to fix it.

Thank you, Parisse.

I see 2 ways to fix this.
1). fix PRINT to handle undef - undef*i
2). convert undef - undef*i to plain undef

I like the 2nd way, because it is more consistent, and we can easily test for it

CAS> z = 0/0      → undef
CAS> z == undef      → 1
CAS> type(z)      → DOM_IDENT

CAS> z = 1e108+1e200*i
CAS> z = z/z      → undef
CAS> z == undef      → 0
CAS> type(z)      → DOM_FLOAT

CAS> z = 1e109+1e200*i
CAS> z = z/z      → undef-undef*i
CAS> z == undef      → 0
CAS> z == undef-undef*i      → 0
CAS> type(z)      → DOM_COMPLEX

Last test RHS is "simplified" to plain undef. But, z is stuck with "complex" undef.
Internally converting all types of undef's to "plain" undef seems better.

What do you think ?