When an expression is evaluated, the port-column is not 0. You can see
this by typing (write (port-column (current-output-port))) at the
repl. This means that when you do ~3t, it will not generate any spaces
as it is already past column 3.

This can be fixed by resetting port-position before we evaluate the REPL
expression.

-- 
Ian Price

"Programming is like pinball. The reward for doing it well is
the opportunity to do it again" - from "The Wizardy Compiled"