> Just out of curiosity: Why does (trace 'if) cause such strange
> behaviour when I try to type in more commands?
Unfortunately, 'trace' can handle built-in functions only when they
evaluate all arguments, which is not the case for 'if'.
After you traced 'if', it was converted to an EXPR function which _does_
evaluate all arguments (not what 'if' is supposed to do, but 'trace'
doesn't know better).
Then, when you type in commands in the line editor, no trace information
is actually printed, because the line editor disables debugging while it
is running so that it won't garble up the debug info of the actual
program. However, as 'if' isn't functioning properly any more, strange