let vs. local

[peter@robots.oxford.ac.uk]

Hi,
	I've been trying to get to grips with the let/local distinctions in
es, and have come up with the following `problem'.  Why are the
following two function defintions different?

1)	fn xx {echo hello; let(fn-xx=) xx; echo bye}
2)	fn xx {echo hello; local(fn-xx=) xx; echo bye}

The first gives me (as expected)
	hello
	xx not found
	bye
and the second prints `hello' ad infinitum.

I find this confusing as these two examples are `equivalent':
1)	fn xx {echo hello; let(yy=bye) echo $yy}
2)	fn xx {echo hello; local(yy=bye) echo $yy}

Could anyone explain why redefining the function in let/local, then calling
that function give differing results?

I stumbled on this problem when I was trying to translate rc's ``builtin''
keyword, I was trying to convert:
	fn rm {builtin rm -i $*} for rc
to
	fn rm {local(fn-rm=) rm -i $*} for es.
Replacing local with let works though :-).

Confused,
	Pete.