Merge from tuebingen/trunk (needed for upcoming fixes to SRFI 19):

r568 | sperber | 2003-12-01 22:42:06 +0100 (Mon, 01 Dec 2003) | 4 lines
Changed paths:
   M /s48/tuebingen/trunk/scheme/bcomp/comp-prim.scm
   M /s48/tuebingen/trunk/scheme/rts/xnum.scm

Subject: Make INEXACT->EXACT work on exacts and vice versa

As discussed on the Scheme 48 mailing list, and requested by jar.

scheme/bcomp/comp-prim.scm

@@ -74,9 +74,9 @@
     (exact?
      ,(proc (number-type) boolean-type))
     (exact->inexact
-     ,(proc (exact-type) inexact-type))
+     ,(proc (number-type) inexact-type))
     (inexact->exact
-     ,(proc (inexact-type) exact-type))
+     ,(proc (number-type) exact-type))
     ((exp log sin cos tan asin acos sqrt)
      ,(proc (number-type) number-type))
     ((atan)

scheme/rts/xnum.scm

@@ -216,9 +216,12 @@
 (define-simple-type :exact (:number)
   (lambda (n) (and (number? n) (exact? n))))
 
+(define-method &inexact->exact ((n :exact)) n)
+
 (define-simple-type :inexact (:number)
   (lambda (n) (and (number? n) (inexact? n))))
 
+(define-method &exact->inexact ((n :inexact)) n)
 
 ; Whattakludge.