[Chicken-users] Re: srfi-45 egg issue

[Kon Lovett]

On Aug 11, 2009, at 11:36 AM, Derrell Piper wrote:

> Hi,
>
> I'm playing around with the srfi-45 egg in Chicken 4.  The third  
> test/benchmark from the SRFI is failing thusly:

Sorry about this; see Rel 2.2.0. Forgot that a lazy recursive promise  
could hold a R5RS promise.

Note that 'delay' is always the R5RS procedure & 'd-lay' (or 'delay- 
recursive') is the SRFI 45 version. This impl violates the SRFI since  
it doesn't redefine the original procedure. ('delay' is primitive  
syntax in Chicken 4 & not so easy to redefine. With Chicken 3, which  
doesn't have a module system, redefining would have blocked use of the  
R5RS 'delay'.)

> csi> (use srfi-45)
> ; loading /usr/local/lib/chicken/4/srfi-45.import.so ...
>
> Warning: re-importing already imported identifier: promise?
>
> Warning: re-importing already imported identifier: force
> ; loading /usr/local/lib/chicken/4/srfi-45.so ...
> csi> (define r (delay (begin (display 'hi) 1)))
> csi> (define s (lazy r))
> csi> (define t (lazy s))
> csi> (recursive-promise? t)
> #t
> csi> (force t)
>
> Error: (force) expected a recursive promise: (#<promise>)
>
>         Call history:
>
>         <syntax>          (force t)
>         <eval>            (force t)       <--

Best Wishes,
Kon