...So, you&#x27;ve never used LISP, or played with a language with eval in it? In either, the above isn&#x27;t exactly built in, but it is trivial to create.<p>But yes, being unaware of the 89, I was talking about the Z80 calculators that make up the rest of the TI-8x range, which are still used in schools to this day, which are programmed in a rubbish version of BASIC called TI-BASIC. It sucks. The 68k calculators, like the 89 and the nspire are programmed in a completely different and much better version of BASIC. This is also called TI-BASIC. This leads to much confusion, and to make it worse, there is a third TI-BASIC, which is also completely different, and was used in the computers made by TI.