Re: eval inside let

[Klaus Schilling <Klaus dot Schilling at munich dot netsurf dot de>]

Keith Wright writes:
 > > From: thi <ttn@mingle.glug.org>
 > > 
 > >   (let ((foo 'bar)) (local-eval (display foo) the-environment))
 > > 
 > > note that you don't need to quote the first arg.
 > 
 > If true, that would be a bug.  The whole point of EVAL is to evaluate
 > an expression constructed on the fly.  If it auto-quotes everything
 > it becomes just a stupid name for the identity function. 
 > 
 > >  (hmm, when i use a quote, guile seems to hang
 > 
 > I dare anybody to say that isn't (or wouldn't be) a bug.
 > 
It's a feature, not a bug

 >  -- does anyone else see this?)
 > 
 > I don't.  I get "ERROR: Unbound variable: the-environment" whether I
 > quote or not.
 > 
 > On the other hand, if you think you need this function (LOCAL-EVAL),
 > you may be way off base.  Ask yourself: how would I write this in C?
Yeah, how would one write it in C without having to recompile stuff?

 > Many people who think they want some flavor of EVAL really want to
 > treat functions as data, which is much simpler.
 > 
May you give a few examples to elucidate the difference?

Klaus Schilling