[Larceny-users] read-dispatch-vec initialization

[William D Clinger]

Ed wrote:
> In Lib/Common/reader.scm :
> 
> (letrec
>     (...
>      (read-dispatch-vec (make-vector 256 (undefined)))
>      ...)
> 
>   ;; initialize read-dispatch-vec :
> 
>   (do ((i 255 (- i 1)))
>        ((< i 0) '())
>     (vector-set! read-dispatch-vec i read-illegal))
>   ...)
> 
> Why isn't it simply:
> 
> (read-dispatch-vec (make-vector 256 read-illegal))

That would violate the letrec restriction of R5RS 4.2.2:
read-dispatch-vec and read-illegal are bound by the same
letrec.

Will