Hi Edwin,
> On Thu, Jul 28, 2011 at 4:48 AM, Tomas Hlavaty <[email protected]> wrote:
> > Hi Edwin,
> >
> >> thinking about it a bit, i can just do away with one and live with the
> >> other? say, can i just live with (bind)?
> >
> > yes, but it is more convenient to write let in your programs instead of
> > the bind with constructing the binding list manually. However, in
> > certain situations, one needs an evaluating version, e.g. when you
> > construct code programmatically. I hit this situation in the wl
>
> reading the docs again after this, (let) evaluates while (bind) does
> not. i hope i got that right.
Yes.
BTW, in the reference evaluated arguments are marked with a quote
(let sym 'any . prg) -> any
(let (sym 'any ..) . prg) -> any
(bind 'sym|lst . prg) -> any
so we see that 'let' doesn't evaluate 'sym', while 'bind' does.
As Tomas said, it is a matter of convenience:
(let A (lines "lib.l")
(* A A) )
If you wanted to use 'bind' for that, you could do
(bind 'A
(setq A (lines "lib.l"))
(* A A) )
or
(bind (list (cons 'A (lines "lib.l")))
(* A A) )
'bind' is more flexible, as the symbols can be determined at runtime,
while 'let' allows for a more readble code.
Cheers,
- Alex
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