* string->number now understands +nan.0, -nan.0, +inf.0 and -inf.0.

src/ikarus.numerics.ss

@@ -2143,6 +2143,13 @@
         (error 'string->number "~s is not a string" x))
       (let ([n (string-length x)])
         (cond
+          [(fx= n (string-length "+xxx.0"))
+           (cond
+             [(string=? x "+inf.0") +inf.0]
+             [(string=? x "-inf.0") -inf.0]
+             [(string=? x "+nan.0") +nan.0]
+             [(string=? x "-nan.0") -nan.0]
+             [else (start x n 0 #f #f)])]
           [(fx> n 0) (start x n 0 #f #f)]
           [else #f]))))
 

src/ikarus.reader.ss

@@ -664,10 +664,10 @@
          (tokenize-decimal-no-digits p (cons c ls) #f)]
         [(char=? c #\i) 
          (read-char* p (cons #\i ls) "nf.0" "number sequence")
-         (/ 1.0 0.0)]
+         +inf.0]
         [(char=? c #\n)
          (read-char* p (cons #\i ls) "an.0" "number sequence")
-         (/ (/ 1.0 0.0) (/ 1.0 0.0))]
+         +nan.0]
         [else (num-error "invalid sequence" (cons c ls))]))) 
   (define (tokenize-integer-no-digits p ls exact? radix?)
     (let ([c (read-char p)])