## Turing Machine in SQL (4/5)

This is the fourth of five posts on this subject.

In previous posts,
I have presented different ways of implementing a Turing Machine (TM) in SQL
with Postgres.
All three techniques rely on `WITH RECURSIVE`

to iterate till the TM stops, so
as to provide some kind of while construct.

In this post, I get rid of this construct, so that the solution does not require
Postgres 8.4 or later.
Obviously there is a trick: I will use a recursive SQL function with side
effects on a `TABLE`

to execute the TM.