fair enough - sufficiently large memory is also necessary. For that reason you couldn't write a Lisp interpreter on the 12C, although you could write one in the

fair enough - sufficiently large memory is also necessary. For that reason you couldn't write a Lisp interpreter on the 12C, although you could write one in the 12C language. The point I was trying to make is that the simplest languages are Turing equivalent (given sufficient memory), because they have the necessary tests and control flow. The TFA goes a bit astray IMHO when it says Turing completeness is not necessary for a language to be useful. Turing completeness is a low bar and even SQL as generally implemented hurdles it. sorry, I wasn't incredibly rigorous or clear.